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A051223 Number of ways of placing n nonattacking superqueens on an n X n board. 24

%I #49 Jan 22 2024 09:08:32

%S 1,0,0,0,0,0,0,0,0,4,44,156,1876,5180,32516,202900,1330622,8924976,

%T 64492432,495864256,3977841852,34092182276,306819842212,2883202816808,

%U 28144109776812,286022102245804

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

%C A superqueen moves like a queen and a knight.

%C A linear-time algorithm giving an explicit solution for any n >= 10 for the n-super-queens-problem can be found at the link. Included is an online solver, implemented in JavaScript. - Frank Schwellinger (nummer_eins(AT)web.de), Mar 19 2004. [But see the next comment - _N. J. A. Sloane_, Jul 01 2021]

%C Escamocher and O'Sullivan (2021) claim Schwellinger's algorithm is incorrect, and that their own algorithm is the first published linear-time algorithm. - _N. J. A. Sloane_, Jul 01 2021

%H D. Bill, <a href="http://www.durangobill.com/N_Queens.html">Durango Bill's The N-Queens Problem</a>

%H Guillaume Escamocher and Barry O'Sullivan, <a href="https://doi.org/10.1016/j.disc.2021.112316">Leprechauns on the chessboard</a>, Discrete Mathematics, 344(5), 2021. See especially page 3.

%H Vaclav Kotesovec, <a href="https://oeis.org/wiki/User:Vaclav_Kotesovec">Non-attacking chess pieces</a>, 6ed.

%H R. Oprisch, <a href="http://oprisch.net/SuperQueens/SuperQueens.html">N x N SuperQueens Solutions Table</a>

%H F. Schwellinger, <a href="https://web.archive.org/web/20050317085130/http://super.info.ms/">Explicit Solution To the N-Super-Queens Problem</a>.

%H W. Schubert, <a href="https://web.archive.org/web/20160410085823/http://m29s20.vlinux.de/~wschub/nqueen.html">N-Queens page</a>

%Y Cf. A051224, A000170.

%K nonn,nice,more

%O 1,10

%A Ulrich Schimke (ulrschimke(AT)aol.com)

%E a(20) from Bill link added Jul 25 2006

%E a(21)-a(23) from R. Oprisch's website added by _Max Alekseyev_, Sep 29 2006

%E a(24)-a(26) from _W. Schubert_, Jul 31 2009, Nov 29 2009, Jan 18 2011

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Last modified March 29 11:45 EDT 2024. Contains 371278 sequences. (Running on oeis4.)