A007545 Number of chess games with n plies (another version).

1, 20, 400, 8902, 197742, 4897256, 120921506, 3284294545, 88867026005

Offset: 0

Author

Ken Thompson (ken(AT)google.com)

Keywords

• fini
• nonn
• hard

Comments

Up to a(6) this is the number of chess games with all legality constraints removed, even allowing the king to be captured. (This differs from the number of positions in suicide chess, as suicide chess contains compulsory captures.) - Richard Bean, Jun 18 2003

References

• N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

Links

• Eric Weisstein's World of Mathematics, Chess
• Index entries for sequences related to number of chess games

Crossrefs

Cf. A006494, A048987.

Extensions

I am not sure of the precise rules that were used to compute these numbers. A006494 and A048987 are the preferred versions of this sequence. - N. J. A. Sloane.