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A129551 Number of ways to place n+2 queens and 2 pawns on an n X n board so that no two queens attack each other. 1
0, 0, 0, 0, 0, 0, 4, 44, 280, 1304, 12452, 105012, 977664, 9239816, 90776620, 897446092 (list; graph; refs; listen; history; internal format)
OFFSET

1,7

LINKS

R. D. Chatham, The N+k Queens Problem Page.

R. D. Chatham, M. Doyle, G. H. Fricke, J. Reitmann, R. D. Skaggs and M. Wolff, Independence and Domination Separation in Chessboard Graphs, Journal of Combinatorial Mathematics and Combinatorial Computing, to appear.

EXAMPLE

a(4)=0 because when 6 queens are placed on a 4 X 4 board, at least two queens will be adjacent and therefore mutually attacking.

CROSSREFS

Cf. A000170, A129552.

Sequence in context: A051223 A077435 A074751 * A202162 A081078 A035014

Adjacent sequences:  A129548 A129549 A129550 * A129552 A129553 A129554

KEYWORD

more,nonn

AUTHOR

R. Douglas Chatham (d.chatham(AT)moreheadstate.edu), Apr 20 2007

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Last modified February 13 03:38 EST 2012. Contains 205435 sequences.