OFFSET
1,5
LINKS
Vincenzo Librandi, Table of n, a(n) for n = 1..1000
Index entries for linear recurrences with constant coefficients, signature (2,4,-10,-5,20,0,-20,5,10,-4,-2,1).
FORMULA
a(n) = n^2*(n-2)*(n-4)*(n^2-6*n+12)/6 if n is even and a(n) = n^2*(n-1)*(n-3)*(n^2-8*n+18)/6 if n is odd. - Vaclav Kotesovec, Jan 31 2010
G.f.: -4*x^5*(9*x^6+94*x^5+199*x^4+388*x^3+151*x^2+94*x+25) / ((x-1)^7*(x+1)^5). - Colin Barker, Jan 09 2013
MATHEMATICA
CoefficientList[Series[- 4 x^4 (9 x^6 + 94 x^5 + 199 x^4 + 388 x^3 + 151 x^2 + 94 x + 25) / ((x - 1)^7 (x + 1)^5), {x, 0, 50}], x] ( * Vincenzo Librandi, May 29 2013 *)
LinearRecurrence[{2, 4, -10, -5, 20, 0, -20, 5, 10, -4, -2, 1}, {0, 0, 0, 0, 100, 576, 2156, 7168, 17496, 41600, 82280, 161280}, 30] (* Harvey P. Dale, Dec 27 2014 *)
CROSSREFS
KEYWORD
nonn,nice,easy
AUTHOR
Vaclav Kotesovec, Feb 05 2010
STATUS
approved