A278830 Maximal number of possible moves at the n-th ply of a chess game.

20, 20, 31, 32, 46, 48, 52, 55, 61, 63

Offset: 1

Author

M. F. Hasler, Nov 29 2016

Keywords

• nonn
• hard
• more
• fini

Comments

In view of the 75-moves rule any chess game is finite.

The largest value appearing in the sequence is thought to be 218. - François Labelle, Dec 01 2016

Examples

			In the initial position of the chess game, each player has 20 possible moves (16 pawn moves and 4 knight moves), and the first (half-)move made by White does not affect the 20 possibilities Black will have thereafter.
At its second move, i.e., ply 3 of the game, White may have as much as 31 possible moves, if White started with e2-e4 as first move, and Black offered a pawn with d7-d5 or f7-f5.
		

Links

• A. Dickins, Record number of legal moves in a legal position, 1968
• OEIS index to sequences related to chess.

Crossrefs

Cf. A278831: minimal number of possible moves at the n-th ply.

Cf. A278832: maximal material difference at the end of the n-th ply.

Cf. A083276.

Extensions

a(3)-a(4) corrected and a(5)-a(10) from François Labelle, Nov 29 2016