

A129552


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 (symmetric solutions count only once).


1



0, 0, 0, 0, 0, 0, 1, 6, 37, 164, 1572, 13133, 122279, 1155103, 11347863, 112182378
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OFFSET

1,8


LINKS

Table of n, a(n) for n=1..16.
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, J. Combin. Math. Combin. Comput. 68 (2009), 317.


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. A002562, A129551.
Sequence in context: A129651 A097297 A047670 * A293800 A327611 A056338
Adjacent sequences: A129549 A129550 A129551 * A129553 A129554 A129555


KEYWORD

more,nonn


AUTHOR

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


STATUS

approved



