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

 

Logo

Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 56th year, we are closing in on 350,000 sequences, and we’ve crossed 9,700 citations (which often say “discovered thanks to the OEIS”).

Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A143877 Number of ways of placing kings with no more than 2 mutual attacks on an n X n chessboard symmetric under horizontal and vertical reflection. 1
1, 2, 1, 7, 4, 55, 17, 576, 129, 13243, 1554, 465675, 35443, 32233206, 1330673, 3746034675, 92945020 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

LINKS

Table of n, a(n) for n=0..16.

CROSSREFS

Sequence in context: A120872 A204771 A141512 * A319464 A019642 A339000

Adjacent sequences:  A143874 A143875 A143876 * A143878 A143879 A143880

KEYWORD

nonn,more,hard

AUTHOR

R. H. Hardin, Sep 04 2008

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 December 6 22:42 EST 2021. Contains 349567 sequences. (Running on oeis4.)