OFFSET
1,4
LINKS
Vincenzo Librandi, Table of n, a(n) for n = 1..1000
Index entries for linear recurrences with constant coefficients, signature (9, -36, 84, -126, 126, -84, 36, -9, 1).
FORMULA
Explicit formula: a(n) = 1/24*n^2*(n^6-54*n^4+1019*n^2-6798), n>=5.
G.f.: x^4*(160*x^9 - 963*x^8 + 2054*x^7 - 1308*x^6 - 963*x^5 - 375*x^4 + 5288*x^3 - 5094*x^2 - 467*x - 12)/(x-1)^9.
MATHEMATICA
CoefficientList[Series[x^3 (160 x^9 - 963 x^8 + 2054 x^7 - 1308 x^6 - 963 x^5 - 375 x^4 + 5288 x^3 - 5094 x^2 -467 x - 12) / (x - 1)^9, {x, 0, 50}], x] (* Vincenzo Librandi, Jun 01 2013 *)
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Vaclav Kotesovec, Jan 07 2011
STATUS
approved