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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 (list; graph; refs; listen; history; text; internal format)
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), 129-141.

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

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Last modified January 23 22:36 EST 2020. Contains 331177 sequences. (Running on oeis4.)