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

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A177758 Number of ways to place 5 nonattacking bishops on an n X n toroidal board. 4
0, 0, 0, 0, 120, 6912, 52920, 466944, 1905120, 8647680, 25613280, 81838080, 198764280, 510478080, 1082161080, 2393997312, 4594961280, 9120190464, 16225246080, 29656350720, 49689816120, 85128088320, 135870624120 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,5

LINKS

Vincenzo Librandi, Table of n, a(n) for n = 1..1000

V. Kotesovec, Non-attacking chess pieces, 6ed, 2013

FORMULA

Explicit formula: 1/240*(n-4)^2*(n-2)^2*n^2*(2n^4 -16n^3 +54n^2 -108n+153 +(10n^2 -60n +135)*(-1)^n).

G.f.: -24x^5*(5x^14 +406x^13 +1333x^12 +14880x^11 +24307x^10 +97498x^9 +95187x^8 +175328x^7 +100307x^6 +93018x^5 +28147x^4 +12832x^3 +1589x^2 +278x+5)/((x-1)^11*(x+1)^9).

MATHEMATICA

CoefficientList[Series[- 24 x^4 (5 x^14 + 406 x^13 + 1333 x^12 + 14880 x^11 + 24307 x^10 + 97498 x^9 + 95187 x^8 + 175328 x^7 + 100307 x^6 + 93018 x^5 + 28147 x^4 + 12832 x^3 + 1589 x^2 + 278 x + 5) / ((x - 1)^11 (x + 1)^9), {x, 0, 50}], x] (* Vincenzo Librandi, May 31 2013 *)

CROSSREFS

Cf. A172129, A177755, A177756, A177757.

Sequence in context: A003438 A222157 A092710 * A055213 A035190 A240934

Adjacent sequences:  A177755 A177756 A177757 * A177759 A177760 A177761

KEYWORD

nonn,easy

AUTHOR

Vaclav Kotesovec, May 13 2010

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 November 12 22:16 EST 2019. Contains 329079 sequences. (Running on oeis4.)