login
This site is supported by donations to The OEIS Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
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 (list; graph; refs; listen; history; text; internal format)
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 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

LINKS

Table of n, a(n) for n=1..26.

R. Oprisch, N x N SuperQueens Solutions Table

D. Bill, Durango Bill's The N-Queens Problem

V. Kotesovec, Non-attacking chess pieces, 6ed

F. Schwellinger, Explicit Solution To the N-Super-Queens Problem.

W. Schubert, N-Queens 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

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent | More pages
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy .

Last modified March 23 22:30 EDT 2017. Contains 283985 sequences.