

A103331


Number of ways to place n+1 queens and a pawn 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, 2, 3, 16, 52, 286, 1403, 8214, 54756, 389833, 2923757, 22932960, 184339572
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OFFSET

1,6


LINKS

Table of n, a(n) for n=1..17.
R. D. Chatham, The N+k Queens Problem Page.
R. D. Chatham, G. H. Fricke and R. D. Skaggs, The Queens Separation Problem, Utilitas Mathematica 69 (2006), 129141.
R. D. Chatham, M. Doyle, G. H. Fricke, J. Reitmann, R. D. Skaggs and M. Wolff, Indepe ndence and Domination Separation in Chessboard Graphs, Journal of Combinatorial Mathematics and Combinatorial Computing, to appear.


EXAMPLE

a(4) = 0 since when 5 queens are placed on a 4 X 4 board, at least two of them will be adjacent and therefore mutually attacking.


CROSSREFS

Cf. A103330, A002562.
Sequence in context: A012358 A012700 A012705 * A052506 A052858 A191416
Adjacent sequences: A103328 A103329 A103330 * A103332 A103333 A103334


KEYWORD

more,nonn


AUTHOR

R. Douglas Chatham (d.chatham(AT)moreheadstate.edu), Jan 31 2005


EXTENSIONS

More terms from R. Douglas Chatham (d.chatham(AT)moreheadstate.edu), Feb 15 2005, Apr 20 2007


STATUS

approved



