The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.



(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A055213 Number of n-piece positions at checkers, for n=1 ... 24. 4
120, 6972, 261224, 7092774, 148688232, 2503611964, 34779531480, 406309208481, 4048627642976, 34778882769216, 259669578902016, 1695618078654976, 9726900031328256, 49134911067979776, 218511510918189056, 852888183557922816 (list; graph; refs; listen; history; text; internal format)



The total number of possible positions is a(1)+...+a(24) = 500995484682338672639.

However, not all of these positions are legal, i.e. reachable from the start position. - Ralf Stephan, Sep 18 2004


Jonathan Schaeffer, N. Burch, Yngvi Bjornsson, Akihiro Kishimoto, Martin Muller, Rob Lake, Paul Lu and Steve Sutphen. "Checkers Is Solved", Science, Vol. 317, September 14, 2007, pp. 1518-1522.

Jonathan Schaeffer, Yngvi Bjornsson, N. Burch, Akihiro Kishimoto, Martin Muller, Rob Lake, Paul Lu and Steve Sutphen. Solving Checkers, International Joint Conference on Artificial Intelligence (IJCAI), pp. 292-297, 2005. Distinguished Paper Prize.


J. Schaeffer, Table of n, a(n) for n = 1..24 (complete sequence)

J. Schaeffer, Chinook: Full sequence and more info

J. Schaeffer, Chinook: Publications

J. Schaeffer and R. Lake, Solving the game of checkers, in: R. Nowakowski (ed.), Games of No Chance (1996), p. 119-133.

Yngvi Bjornsson, N. Burch, Rob Lake, Joe Culberson, Paul Lu, Jonathan Schaeffer, Steve Sutphen, Chinook: Total Number of Positions


n=1: A red piece can go on any of 28 squares (it can't reside on the last row) and a red king can be on any of 32 squares. Double that to include black, total of 120.


A133803(n) = floor log a(n).

Sequence in context: A222157 A092710 A177758 * A035190 A240934 A035815

Adjacent sequences:  A055210 A055211 A055212 * A055214 A055215 A055216




Jud McCranie, Jun 23 2000



Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified April 6 12:08 EDT 2020. Contains 333273 sequences. (Running on oeis4.)