|
%I #10 Apr 17 2022 01:00:41
%S 1,21,441,9872,220447,5247292,124278971,3113440755,77520962327,
%T 2024021927610
%N Number of possible chess games at the end of the n-th ply starting without queens.
%C Gives the number of possible chess games where both sides start without queens. Queens are still allowed to appear later in the game through promotion.
%C Does not include games which end in fewer than n plies.
%C The total number of such games should be less than the total number of standard chess games, and it appears A285873(n) <= A048987(n) for n >= 7.
%C Initial terms computed using the Chesspresso engine.
%H <a href="http://www.chesspresso.org/">Chesspresso<sup>TM</sup></a>.
%e a(1) = 21 because there are 20 usual opening moves plus the additional move of moving the king into the vacant square where the queen would usually be.
%Y Cf. A048987 (standard), A285874 (no rooks), A285875 (no knights), A285876 (no bishops), A285877 (no pawns), A285878 (pawns and king).
%K nonn,hard,more,fini
%O 0,2
%A _Sean A. Irvine_, Apr 28 2017
| 