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Maximum number of moves available to one side from a legal chess position with n pieces (with no additional pieces from promotion).
2

%I #5 Jul 24 2016 20:34:47

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

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

%C 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.

%C 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).

%C 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.

%H T. Krabbé, <a href="http://timkr.home.xs4all.nl/chess2/diary_10.htm">Open Chess Diary, Item 195, Nov 29 2002: Mobility records</a>

%H Rick L. Shepherd, <a href="/A275360/a275360.txt">Positions supporting initial terms and lower bounds.</a>

%K nonn,fini,more

%O 2,1

%A _Rick L. Shepherd_, Jul 24 2016