A275360 Maximum number of moves available to one side from a legal chess position with n pieces (with no additional pieces from promotion).

8, 35, 49, 63, 74, 85, 93, 99, 103, 109, 115

Offset: 2

Author

Rick L. Shepherd, Jul 24 2016

Keywords

• nonn
• fini
• more

Comments

For completeness: If a side has two Bishops, those Bishops must be on opposite-colored squares (as in the original board configuration). Four promotion moves (to Knight, Bishop, Rook, or Queen) are available per Pawn per promotion square.

Sequence inspired by the Tim Krabbé link and a posting by Bernhard Sadlowski to rec.games.chess.computer on Oct 30 1996 (giving the H. H. Cross position -- see this a-file -- which supports the a(32) lower bound).

Terms a(13) through a(32) are respectively >= 119, 125, 129, 133, 137, 139, 140, 141, 143, 144, 144, 144, 144, 143, 142, 139, 128, 117, 105, 99.

Links

• T. Krabbé, Open Chess Diary, Item 195, Nov 29 2002: Mobility records
• Rick L. Shepherd, Positions supporting initial terms and lower bounds.