The OEIS mourns the passing of Jim Simons and is grateful to the Simons Foundation for its support of research in many branches of science, including the OEIS.
login
The OEIS is supported by the many generous donors to the OEIS Foundation.

 

Logo
Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A172966 Number of ways to place 4 nonattacking knights on an n X n cylindrical board. 2
0, 0, 0, 306, 2365, 19047, 90503, 328324, 981693, 2547955, 5933257, 12681288, 25284363, 47595023, 85357395, 146879312, 243867873, 392452803, 614423653, 938708560, 1403123967, 2056426383, 2960698943, 4194107208, 5854060325 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,4
LINKS
FORMULA
a(n) = n*(n^7-54n^5+72n^4+1115n^3-2616n^2-8502n+26712)/24, n>=9.
G.f.: x^4*(76*x^13-684*x^12+2856*x^11-7714*x^10+16164*x^9-29151*x^8+45506*x^7-57766*x^6+55629*x^5-39385*x^4+21484*x^3-8778*x^2+389*x-306)/(x-1)^9. - Vaclav Kotesovec, Mar 25 2010
MATHEMATICA
CoefficientList[Series[x^3 (76 x^13 - 684 x^12 + 2856 x^11 - 7714 x^10 + 16164 x^9 - 29151 x^8 + 45506 x^7 - 57766 x^6 + 55629 x^5 - 39385 x^4 + 21484 x^3 - 8778 x^2 + 389 x - 306) / (x - 1)^9, {x, 0, 50}], x] (* Vincenzo Librandi, May 29 2013 *)
CROSSREFS
Sequence in context: A158589 A030030 A206679 * A223073 A064257 A221854
KEYWORD
nonn,easy
AUTHOR
Vaclav Kotesovec, Feb 06 2010
EXTENSIONS
More terms from Vincenzo Librandi, May 29 2013
STATUS
approved

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

License Agreements, Terms of Use, Privacy Policy. .

Last modified June 14 13:49 EDT 2024. Contains 373400 sequences. (Running on oeis4.)