3x+1 Class records calculation progress map
Status of the 3x+1 class record progress as of: Feb 4, 2012. Intervals are indicated in blocks of 20,000,000,000,000 (20 E+12 or 20 trillion numbers). Calculation of a single block takes approximately 20 days of (idle) time on a Pentium 1000 MHz. All class records found so far can be viewed on the class records page. This project can only run because of many cooperating contributors. If you would like to contribute one or more blocks please go to the search page. Note : the 3x+1 problem is just one of many distributed projects on the internet.
Progress history January 30 2012 :  All blocks up to 121,500 completed. Final missing class record below 2000 found. December 11 2011 :  All blocks up to 120,200 completed. November 11 2011 :  All blocks up to 120,020 completed. One class record confirmed. October 30 2011 :  All blocks up to 118,400 completed, passing 13.253 (~117,094 E+12) October 16 2011 :  All blocks up to 117,000 completed. One more class record confirmed. September 1 2011 :  All blocks up to 113,080 completed. One more class record confirmed. July 31 2011 :  All blocks up to 110,040 completed. One more class record confirmed. July 23 2011 :  All blocks up to 107,500 completed. Delay record 2254 and three class records confirmed. July 21 2011 :  All blocks up to 102,400 completed. July 12 2011 :  All blocks up to 99,200 completed. April 2011 :  All blocks up to 97,080 completed. Delay Record 2091 and two other class records confirmed. November 2010 :  All blocks up to 91,880 completed. Three class records confirmed. August 2010 :  All blocks up to 90,000 completed. Four more class records confirmed. February 2010 :  All blocks up to 82,700 completed. Two class records confirmed. June 2009 :  All blocks up to 76,160 completed. The lowest missing CR (1964) and one other confirmed. April 2009 :  All blocks up to 72,520 completed, passing 256. Three class records confirmed. February 2009 :  All blocks up to 71,020 completed. One more class record confirmed. December 2008 :  All blocks up to 69,740 completed. The lowest missing CR (1951) and two more confirmed. November 2008 :  All blocks up to 67,500 completed. Class record 2000 finally confirmed. October 2008 :  All blocks up to 66,380 completed. Four more class records confirmed. May 2008 :  All blocks up to 61,160 completed. The lowest missing CR (1925) and three others confirmed. December 2007 :  All blocks up to 58,600 completed. Four class records confirmed. April 2007 :  All blocks up to 54,540 completed. Five more class records confirmed. October 2006 :  All blocks up to 50,000 completed. Delay Record 2090 and five class records confirmed. November 2005 :  All blocks up to 46,100 completed. Double of Record 2045 confirmed as Delay Record 2046. August 2005 :  All blocks up to 45,040 completed. Five class records confirmed. May 2005 :  Delay Record of 2090 found at ±46,785 E+12 by Eric February 2005 :  All blocks up to 42,060 completed. Three more class record confirmed. November 2004 :  All blocks up to 40,000 completed. Four class records confirmed. August 2004 :  All blocks up to 37,500 completed. Another four class records confirmed. May 2004 :  All blocks up to 36,120 completed. Seven class records confirmed. January 2004 :  All blocks up to 31,960 completed. Five further class records confirmed. November 2003 :  All blocks up to 29,840 completed. One more class record confirmed. August 2003 :  All blocks up to 29,240 completed. Another fifteen class records confirmed. April 2003 :  All blocks up to 23,100 completed. Delay record 2045 and seven class records confirmed. December 2002 :  All blocks up to 20,100 completed. All class records below 1900 known. November 2002 :  All blocks up to 20,000 completed. Delay record 2042 and fourteen class records confirmed. November 2002 :  Delay Record of 2045 found at ±22,702 E+12 by Kevin July 2002 :  All blocks up to 16,460 completed. Delay record 2039 and fifteen class records confirmed. April 2002 :  All blocks up to 12,720 completed. Another fourteen class records confirmed. March 2002 :  Delay Record of 2042 found at ±17,026 E+12 by Michael February 2002 :  All blocks up to 9340 completed. Two more class records confirmed. December 2001 :  Delay Record of 2039 found at ±12,770 E+12 by Billy November 2001 :  All blocks up to 9020 completed. One Delay record and ten class records confirmed. September 2001 :  All blocks up to 6800 completed. Three Delay records and fourteen class records confirmed.  August 2001 :  All blocks up to 3600 completed. Two Delay records and five class records confirmed June 2001 :  Delay Record of 1958 found at ±7579 E+12 by Kevin May 2001 :  Delay Record of 1919 found at ±6482 E+12 by Kevin April 2001 :  Delay Record of 1916 found at ±4861 E+12 by Kevin March 2001 :  Delay Record of 1903 found at ±4320 E+12 by Kevin March 2001 :  Delay Record of 1895 found at ±3586 E+12 by Eric March 2001 :  Delay Record of 1874 found at ±2978 E+12 by Kevin February 2001 :  All blocks up to 2620 completed. Three class records confirmed. January 2001 :  New Class and Delay Record of 1871 found at 2234,047405,400065.
Range 2000-20000 completed (view)		Range 20000-40000 completed (view)		Range 40000-60000 completed (view)		Range 60000-80000 completed (view)		Range 80000-100000 completed (view)
Range 100000-120000 completed (view)
Not yet assigned		Assigned, not yet started		Less than 50% completed		More than 50% completed		Entire interval completed
120000-20 Eric	120020-40 Eric	120040-60 Eric	120060-80 Eric	120080-00 Eric	120100-20 Eric	120120-40 Eric	120140-60 Eric	120160-80 Eric	120180-00 Eric
120200-20 Eric	120220-40 Eric	120240-60 Eric	120260-80 Eric	120280-00 Eric	120300-20 Eric	120320-40 Eric	120340-60 Eric	120360-80 Eric	120380-00 Eric
120400-20 Eric	120420-40 Eric	120440-60 Eric	120460-80 Eric	120480-00 Eric	120500-20 Eric	120520-40 Eric	120540-60 Eric	120560-80 Eric	120580-00 Eric
120600-20 Eric	120620-40 Eric	120640-60 Eric	120660-80 Eric	120680-00 Eric	120700-20 Eric	120720-40 Eric	120740-60 Eric	120760-80 Eric	120780-00 Eric
120800-20 Eric	120820-40 Eric	120840-60 Eric	120860-80 Eric	120880-00 Eric	120900-20 Eric	120920-40 Eric	120940-60 Eric	120960-80 Eric	120980-00 Eric
121000-20 Stephen	121020-40 Stephen	121040-60 Ken	121060-80 Ken	121080-00 Steven	121100-20 Luiz	121120-40 Luiz	121140-60 Luiz	121160-80 Luiz	121180-00 Luiz
121200-20 Stephen	121220-40 Stephen	121240-60 Steven	121260-80 Steven	121280-00 Steven	121300-20 Tom	121320-40 Tom	121340-60 Tom	121360-80 Tom	121380-00 Tom
121400-20 Stephen	121420-40 Stephen	121440-60 Stephen	121460-80 Stephen	121480-00 Fouad	121500-20 Fouad	121520-40 Fouad	121540-60 Fouad	121560-80 Fouad	121580-00 Fouad
121600-20 Steven	121620-40 Steven	121640-60 Steven	121660-80 Steven	121680-00 Bernhard	121700-20 Bob	121720-40 Bob	121740-60 Bob	121760-80 Bob	121780-00 Bob
121800-20 Bob	121820-40 Bob	121840-60 Bob	121860-80 Bob	121880-00 Bob	121900-20 Luiz	121920-40 Luiz	121940-60 Luiz	121960-80 Luiz	121980-00 Luiz
122000-20 Kevin	122020-40 Kevin	122040-60 Kevin	122060-80 Kevin	122080-00 Kevin	122100-20 Kevin	122120-40 Kevin	122140-60 Kevin	122160-80 Kevin	122180-00 Kevin
122200-20 Kevin	122220-40 Kevin	122240-60 Kevin	122260-80 Kevin	122280-00 Kevin	122300-20 Kevin	122320-40 Kevin	122340-60 Kevin	122360-80 Kevin	122380-00 Kevin
122400-20 Kevin	122420-40 Kevin	122440-60 Kevin	122460-80 Kevin	122480-00 Kevin	122500-20 Kevin	122520-40 Kevin	122540-60 Kevin	122560-80 Kevin	122580-00 Kevin
122600-20 Kevin	122620-40 Kevin	122640-60 Kevin	122660-80 Kevin	122680-00 Kevin	122700-20 Kevin	122720-40 Kevin	122740-60 Kevin	122760-80 Kevin	122780-00 Kevin
122800-20 Kevin	122820-40 Kevin	122840-60 Kevin	122860-80 Kevin	122880-00 Kevin	122900-20 Kevin	122920-40 Kevin	122940-60 Kevin	122960-80 Kevin	122980-00 Kevin
123000-20 Kevin	123020-40 Kevin	123040-60 Kevin	123060-80 Kevin	123080-00 Kevin	123100-20 Kevin	123120-40 Kevin	123140-60 Kevin	123160-80 Kevin	123180-00 Kevin
123200-20 Kevin	123220-40 Kevin	123240-60 Kevin	123260-80 Kevin	123280-00 Kevin	123300-20 Kevin	123320-40 Kevin	123340-60 Kevin	123360-80 Kevin	123380-00 Kevin
123400-20 Kevin	123420-40 Kevin	123440-60 Kevin	123460-80 Kevin	123480-00 Kevin	123500-20 Kevin	123520-40 Kevin	123540-60 Kevin	123560-80 Kevin	123580-00 Kevin
123600-20 Kevin	123620-40 Kevin	123640-60 Kevin	123660-80 Kevin	123680-00 Kevin	123700-20 Kevin	123720-40 Kevin	123740-60 Kevin	123760-80 Kevin	123780-00 Kevin
123800-20 Kevin	123820-40 Kevin	123840-60 Kevin	123860-80 Kevin	123880-00 Kevin	123900-20 Kevin	123920-40 Kevin	123940-60 Kevin	123960-80 Kevin	123980-00 Kevin
124000-20 Luiz	124020-40 Kevin	124040-60 Kevin	124060-80 Kevin	124080-00 Kevin	124100-20 Kevin	124120-40 Kevin	124140-60 Kevin	124160-80 Kevin	124180-00 Kevin
124200-20 Kevin	124220-40 Kevin	124240-60 Kevin	124260-80 Kevin	124280-00 Kevin	124300-20 Kevin	124320-40 Kevin	124340-60 Kevin	124360-80 Kevin	124380-00 Kevin
124400-20 Kevin	124420-40 Kevin	124440-60 Kevin	124460-80 Kevin	124480-00 Kevin	124500-20 Kevin	124520-40 Kevin	124540-60 Kevin	124560-80 Kevin	124580-00 Kevin
124600-20 Kevin	124620-40 Kevin	124640-60 Kevin	124660-80 Kevin	124680-00 Kevin	124700-20 Kevin	124720-40 Kevin	124740-60 Kevin	124760-80 Kevin	124780-00 Kevin
124800-20 Kevin	124820-40 Kevin	124840-60 Kevin	124860-80 Kevin	124880-00 Kevin	124900-20 Kevin	124920-40 Kevin	124940-60 Kevin	124960-80 Kevin	124980-00 Kevin
125000-20 Tom	125020-40 Tom	125040-60 Tom	125060-80 Tom	125080-00 Tom	125100-20 Steven	125120-40 Steven	125140-60 Steven	125160-80 Steven	125180-00 Ken
125200-20 Ken	125220-40 Steven	125240-60 Steven	125260-80 Steven	125280-00 Steven	125300-20 Luiz	125320-40 Luiz	125340-60 Luiz	125360-80 Luiz	125380-00 Luiz
125400-20 Eric	125420-40 Eric	125440-60 Eric	125460-80 Eric	125480-00 Eric	125500-20 Eric	125520-40 Eric	125540-60 Eric	125560-80 Eric	125580-00 Eric
125600-20 Stephen	125620-40 Stephen	125640-60 Bernhard	125660-80	125680-00	125700-20 Tom	125720-40 Tom	125740-60 Tom	125760-80 Tom	125780-00 Tom
125800-20 Stephen	125820-40 Stephen	125840-60 Stephen	125860-80 Stephen	125880-00 Stephen	125900-20 Stephen	125920-40 Stephen	125940-60 Stephen	125960-80 Stephen	125980-00 Stephen
126000-20 Kevin	126020-40 Kevin	126040-60 Kevin	126060-80 Kevin	126080-00 Kevin	126100-20 Kevin	126120-40 Kevin	126140-60 Kevin	126160-80 Kevin	126180-00 Kevin
126200-20 Kevin	126220-40 Kevin	126240-60 Kevin	126260-80 Kevin	126280-00 Kevin	126300-20 Kevin	126320-40 Kevin	126340-60 Kevin	126360-80 Kevin	126380-00 Kevin
126400-20 Kevin	126420-40 Kevin	126440-60 Kevin	126460-80 Kevin	126480-00 Kevin	126500-20 Kevin	126520-40 Kevin	126540-60 Kevin	126560-80 Kevin	126580-00 Kevin
126600-20 Kevin	126620-40 Kevin	126640-60 Kevin	126660-80 Kevin	126680-00 Kevin	126700-20 Kevin	126720-40 Kevin	126740-60 Kevin	126760-80 Kevin	126780-00 Kevin
126800-20 Kevin	126820-40 Kevin	126840-60 Kevin	126860-80 Kevin	126880-00 Kevin	126900-20 Kevin	126920-40 Kevin	126940-60 Kevin	126960-80 Kevin	126980-00 Kevin
127000-20 Kevin	127020-40 Kevin	127040-60 Kevin	127060-80 Kevin	127080-00 Kevin	127100-20 Kevin	127120-40 Kevin	127140-60 Kevin	127160-80 Kevin	127180-00 Kevin
127200-20 Kevin	127220-40 Kevin	127240-60 Kevin	127260-80 Kevin	127280-00 Kevin	127300-20 Kevin	127320-40 Kevin	127340-60 Kevin	127360-80 Kevin	127380-00 Kevin
127400-20 Kevin	127420-40 Kevin	127440-60 Kevin	127460-80 Kevin	127480-00 Kevin	127500-20 Kevin	127520-40 Kevin	127540-60 Kevin	127560-80 Kevin	127580-00 Kevin
127600-20 Kevin	127620-40 Kevin	127640-60 Kevin	127660-80 Kevin	127680-00 Kevin	127700-20 Kevin	127720-40 Kevin	127740-60 Kevin	127760-80 Kevin	127780-00 Kevin
127800-20 Kevin	127820-40 Kevin	127840-60 Kevin	127860-80 Kevin	127880-00 Kevin	127900-20 Kevin	127920-40 Kevin	127940-60 Kevin	127960-80 Kevin	127980-00 Kevin
128000-20 Kevin	128020-40 Kevin	128040-60 Kevin	128060-80 Kevin	128080-00 Kevin	128100-20 Kevin	128120-40 Kevin	128140-60 Kevin	128160-80 Kevin	128180-00 Kevin
128200-20 Kevin	128220-40 Kevin	128240-60 Kevin	128260-80 Kevin	128280-00 Kevin	128300-20 Kevin	128320-40 Kevin	128340-60 Kevin	128360-80 Kevin	128380-00 Kevin
128400-20 Kevin	128420-40 Kevin	128440-60 Kevin	128460-80 Kevin	128480-00 Kevin	128500-20 Kevin	128520-40 Kevin	128540-60 Kevin	128560-80 Kevin	128580-00 Kevin
128600-20 Kevin	128620-40 Kevin	128640-60 Kevin	128660-80 Kevin	128680-00 Kevin	128700-20 Kevin	128720-40 Kevin	128740-60 Kevin	128760-80 Kevin	128780-00 Kevin
128800-20 Kevin	128820-40 Kevin	128840-60 Kevin	128860-80 Kevin	128880-00 Kevin	128900-20 Kevin	128920-40 Kevin	128940-60 Kevin	128960-80 Kevin	128980-00 Kevin
129000-20 Kevin	129020-40 Kevin	129040-60 Kevin	129060-80 Kevin	129080-00 Kevin	129100-20 Kevin	129120-40 Kevin	129140-60 Kevin	129160-80 Kevin	129180-00 Kevin
129200-20 Kevin	129220-40 Kevin	129240-60 Kevin	129260-80 Kevin	129280-00 Kevin	129300-20 Kevin	129320-40 Kevin	129340-60 Kevin	129360-80 Kevin	129380-00 Kevin
129400-20 Kevin	129420-40 Kevin	129440-60 Kevin	129460-80 Kevin	129480-00 Kevin	129500-20 Kevin	129520-40 Kevin	129540-60 Kevin	129560-80 Kevin	129580-00 Kevin
129600-20 Kevin	129620-40 Kevin	129640-60 Kevin	129660-80 Kevin	129680-00 Kevin	129700-20 Kevin	129720-40 Kevin	129740-60 Kevin	129760-80 Kevin	129780-00 Kevin
129800-20 Kevin	129820-40 Kevin	129840-60 Kevin	129860-80 Kevin	129880-00 Kevin	129900-20 Kevin	129920-40 Kevin	129940-60 Kevin	129960-80 Kevin	129980-00 Kevin
130000-20 Kevin	130020-40 Kevin	130040-60 Kevin	130060-80 Kevin	130080-00 Kevin	130100-20 Kevin	130120-40 Kevin	130140-60 Kevin	130160-80 Kevin	130180-00 Kevin
130200-20 Kevin	130220-40 Kevin	130240-60 Kevin	130260-80 Kevin	130280-00 Kevin	130300-20 Kevin	130320-40 Kevin	130340-60 Kevin	130360-80 Kevin	130380-00 Kevin
130400-20 Kevin	130420-40 Kevin	130440-60 Kevin	130460-80 Kevin	130480-00 Kevin	130500-20 Kevin	130520-40 Kevin	130540-60 Kevin	130560-80 Kevin	130580-00 Kevin
130600-20 Kevin	130620-40 Kevin	130640-60 Kevin	130660-80 Kevin	130680-00 Kevin	130700-20 Kevin	130720-40 Kevin	130740-60 Kevin	130760-80 Kevin	130780-00 Kevin
130800-20 Kevin	130820-40 Kevin	130840-60 Kevin	130860-80 Kevin	130880-00 Kevin	130900-20 Kevin	130920-40 Kevin	130940-60 Kevin	130960-80 Kevin	130980-00 Kevin
131000-20 Kevin	131020-40 Kevin	131040-60 Kevin	131060-80 Kevin	131080-00 Kevin	131100-20 Kevin	131120-40 Kevin	131140-60 Kevin	131160-80 Kevin	131180-00 Kevin
131200-20 Kevin	131220-40 Kevin	131240-60 Kevin	131260-80 Kevin	131280-00 Kevin	131300-20 Kevin	131320-40 Kevin	131340-60 Kevin	131360-80 Kevin	131380-00 Kevin
131400-20 Kevin	131420-40 Kevin	131440-60 Kevin	131460-80 Kevin	131480-00 Kevin	131500-20 Kevin	131520-40 Kevin	131540-60 Kevin	131560-80 Kevin	131580-00 Kevin
131600-20 Kevin	131620-40 Kevin	131640-60 Kevin	131660-80 Kevin	131680-00 Kevin	131700-20 Kevin	131720-40 Kevin	131740-60 Kevin	131760-80 Kevin	131780-00 Kevin
131800-20 Kevin	131820-40 Kevin	131840-60 Kevin	131860-80 Kevin	131880-00 Kevin	131900-20 Kevin	131920-40 Kevin	131940-60 Kevin	131960-80 Kevin	131980-00 Kevin
132000-20 Luiz	132020-40 Luiz	132040-60 Luiz	132060-80 Luiz	132080-00 Luiz	132100-20 Tom	132120-40 Tom	132140-60 Tom	132160-80 Tom	132180-00 Tom
132200-20 Steven	132220-40 Steven	132240-60 Steven	132260-80 Steven	132280-00	132300-20	132320-40	132340-60	132360-80	132380-00
132400-20	132420-40	132440-60	132460-80	132480-00	132500-20 Eric	132520-40 Eric	132540-60 Eric	132560-80 Eric	132580-00 Eric
132600-20 Eric	132620-40 Eric	132640-60 Eric	132660-80 Eric	132680-00 Eric	132700-20 Eric	132720-40 Eric	132740-60 Eric	132760-80 Eric	132780-00 Eric
132800-20	132820-40	132840-60	132860-80	132880-00	132900-20	132920-40	132940-60	132960-80	132980-00
Contributions by Eric Eric Roosendaal, Netherlands (author) Kevin Kevin Hebb, Alberta, Canada Ken Ken Monks, Pennsylvania, USA Bob Bob Coffman, USA Bernhard Bernhard Willems, Germany Steven Steven Cuthbert, England Luiz Luiz Antonio Souza, Brazil Stephen Stephen Dickason Tom Tom Leong, USA Fouad Fouad Dehlawi, Saudi Arabia

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