

A089957


Number of chess positions that can be obtained in exactly one way in n plies.


2



1, 20, 400, 1862, 9825, 53516, 311642, 2018993, 12150635, 69284509, 382383387, 1994236773
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OFFSET

0,2


COMMENTS

Definition: position = position with castling and en passant information, diagram = position without castling and en passant information.
The positions are taken from the sets that are counted in A083276.


LINKS

Table of n, a(n) for n=0..11.
F. Labelle, Statistics on chess positions
P. Österlund, Computation of a(11).
Index entries for sequences related to number of chess games


CROSSREFS

Cf. A083276, A090051.
Sequence in context: A208559 A209080 A090051 * A267718 A207402 A207751
Adjacent sequences: A089954 A089955 A089956 * A089958 A089959 A089960


KEYWORD

nonn,hard,more,fini


AUTHOR

François Labelle, Jan 12 2004


EXTENSIONS

a(9) from François Labelle, Mar 09 2004
a(10) from Arkadiusz Wesolowski, Jan 04 2012
a(11) from Peter Österlund on Feb 22 2013, verified by François Labelle on Jan 08 2017


STATUS

approved



