The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A189851 Number of ways to place n nonattacking composite pieces rook + rider[1,4] on an n X n chessboard. 5
 1, 2, 6, 24, 48, 182, 868, 5752, 22952, 131766, 912964, 7556978, 52602390, 432795244, 4121203656, 44335718598, 416447624724 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS In fairy chess, the rider [1,4] is called a Girafferider. a(n) is also number of permutations p of 1,2,...,n satisfying |p(i+k)-p(i)|<>4k AND |p(j+4k)-p(j)|<>k for all i>=1, j>=1, k>=1, i+k<=n, j+4k<=n LINKS V. Kotesovec, Number of ways of placing non-attacking queens, kings, bishops and knights (in English and Czech) Wikipedia, Fairy chess piece CROSSREFS Cf. A000170, A189837, A189850 Sequence in context: A092485 A113904 A099144 * A189563 A321613 A104114 Adjacent sequences:  A189848 A189849 A189850 * A189852 A189853 A189854 KEYWORD nonn,hard AUTHOR Vaclav Kotesovec, Apr 29 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
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified February 19 09:57 EST 2020. Contains 332041 sequences. (Running on oeis4.)