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A285876
Number of possible chess games at the end of the n-th ply starting without bishops.
7
1, 22, 484, 11248, 260904, 6434922, 158069690, 4126252938, 107097735673, 2940365284820
OFFSET
0,2
COMMENTS
Gives the number of possible chess games where both sides start without bishops.
Does not include games which end in fewer than n plies.
The initial terms exceed the corresponding terms in A048987, but this should eventually reverse and we should have A285876(n) <= A048987(n) for large enough n.
Initial terms computed using the Chesspresso engine.
EXAMPLE
a(1) = 22 because we have the standard 20 opening moves, plus the queen and king can each move into the squares that would normally contain the bishops.
CROSSREFS
Cf. A048987 (standard), A285873 (no queens), A285874 (no rooks), A285875 (no knights), A285877 (no pawns), A285878 (pawns and king).
Sequence in context: A223970 A171296 A009966 * A041221 A041926 A230350
KEYWORD
nonn,hard,more,fini
AUTHOR
Sean A. Irvine, Apr 28 2017
STATUS
approved