A285876 Number of possible chess games at the end of the n-th ply starting without bishops.

1, 22, 484, 11248, 260904, 6434922, 158069690, 4126252938, 107097735673, 2940365284820

Offset: 0

Author

Sean A. Irvine, Apr 28 2017

Keywords

• nonn
• hard
• more
• fini

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.

Examples

			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.
		

Links

• Chesspresso^TM.

Crossrefs

Cf. A048987 (standard), A285873 (no queens), A285874 (no rooks), A285875 (no knights), A285877 (no pawns), A285878 (pawns and king).