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

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A189838 Number of ways to place n nonattacking composite pieces rook + rider[2,2] on an n X n chessboard. 5
1, 2, 4, 16, 36, 128, 672, 4264, 25044, 173712, 1318904, 11069056, 96808692, 927478976, 9435033872, 103783608480, 1195155968388 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

a(n) is also number of permutations p of 1,2,...,n satisfying |p(j+2k)-p(j)|<>2k for all j>=1, k>=1, j+2k<=n

LINKS

Table of n, a(n) for n=1..17.

V. Kotesovec, Number of ways of placing non-attacking queens, kings, bishops and knights (in English and Czech)

Wikipedia, Fairy chess piece

CROSSREFS

Cf. A110128, A000170

Sequence in context: A101926 A087965 A074411 * A247219 A265835 A185074

Adjacent sequences:  A189835 A189836 A189837 * A189839 A189840 A189841

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.

License Agreements, Terms of Use, Privacy Policy. .

Last modified May 18 10:19 EDT 2021. Contains 343995 sequences. (Running on oeis4.)