

A051223


Number of ways of placing n nonattacking superqueens on an n X n board.


20



1, 0, 0, 0, 0, 0, 0, 0, 0, 4, 44, 156, 1876, 5180, 32516, 202900, 1330622, 8924976, 64492432, 495864256, 3977841852, 34092182276, 306819842212, 2883202816808, 28144109776812, 286022102245804
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OFFSET

1,10


COMMENTS

A superqueen moves like a queen and a knight.
A linear time algorithm giving an explicit solution for any n >= 10 for the nsuperqueensproblem can be found at the link. Included is an online solver, implemented in Javascript.  Frank Schwellinger (nummer_eins(AT)web.de), Mar 19 2004


LINKS

Table of n, a(n) for n=1..26.
R. Oprisch, N x N SuperQueens Solutions Table
D. Bill, Durango Bill's The NQueens Problem
V. Kotesovec, Nonattacking chess pieces, 6ed
F. Schwellinger, Explicit Solution To the NSuperQueens Problem.
W. Schubert, NQueens page


CROSSREFS

Cf. A051224, A000170.
Sequence in context: A193448 A200456 A053314 * A265081 A077435 A271294
Adjacent sequences: A051220 A051221 A051222 * A051224 A051225 A051226


KEYWORD

nonn,nice,more


AUTHOR

Ulrich Schimke (ulrschimke(AT)aol.com)


EXTENSIONS

a(20) from Bill link added Jul 25 2006
a(21)a(23) from R. Oprisch's website added by Max Alekseyev, Sep 29 2006
a(24)a(26) from W. Schubert, Jul 31 2009, Nov 29 2009, Jan 18 2011


STATUS

approved



