A090051 Number of chess diagrams that can be obtained in exactly one way in n plies. This is also the number of dual-free proof games in n plies.

1, 20, 400, 1862, 9373, 51323, 298821, 1965313, 11759158, 66434263, 365037821, 1895313862

Offset

0,2

Comments

Chess diagrams are chess positions without regard to whether castling or en passant capturing is possible. They are counted in A019319. A proof game is a classic type of chess problem.

Links

Table of n, a(n) for n=0..11.

F. Labelle, Statistics on chess positions

Index entries for sequences related to number of chess games

Crossrefs

Cf. A019319, A089957, A209080.

Sequence in context: A208017 A208559 A209080 * A089957 A267718 A207402

Adjacent sequences: A090048 A090049 A090050 * A090052 A090053 A090054

Keyword

nonn,hard,more,nice,fini

Author

François Labelle, Jan 19 2004

Extensions

a(9)-a(10) from Arkadiusz Wesolowski, Jan 04 2012

a(11) from François Labelle, Jan 16 2017

Status

approved