

A048987


Number of possible chess games at the end of the nth ply.


17



1, 20, 400, 8902, 197281, 4865609, 119060324, 3195901860, 84998978956, 2439530234167, 69352859712417, 2097651003696806, 62854969236701747, 1981066775000396239, 61885021521585529237, 2015099950053364471960
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OFFSET

0,2


COMMENTS

Does not include games which end in fewer than n plies.
According to the laws of chess, the "50move rule" and "draw by 3fold repetition" do not prevent infinite games because they require an appeal by one of the players, but the "75move rule" introduced on Jul 01 2014 is automatic and makes chess finite.  François Labelle, Mar 30 2015


LINKS



CROSSREFS



KEYWORD

nonn,nice,hard,more,fini


AUTHOR



EXTENSIONS

a(11) from François Labelle, Jul 25 2004, who thanks Joost de Heer for providing computer time
a(14) from Richard Bean on Jul 24 2018, value from Peter Osterlund and Ankan Banerjee
a(15) from Paul Barnett on Jul 04 2022, value from wikipedia page "Shannon number"


STATUS

approved



