OFFSET
1,3
LINKS
Colin Barker, Table of n, a(n) for n = 1..1000
Index entries for linear recurrences with constant coefficients, signature (4,-6,4,-1).
FORMULA
From Colin Barker, Dec 29 2015: (Start)
a(n) = (4*n^3+3*n^2-37*n+30)/6.
a(n) = 4*a(n-1)-6*a(n-2)+4*a(n-3)-a(n-4) for n>4.
G.f.: x^3*(9-5*x) / (1-x)^4.
(End)
PROG
(PARI) concat(vector(2), Vec(x^3*(9-5*x)/(1-x)^4 + O(x^50))) \\ Colin Barker, May 05 2016
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Philippe A.J.G. Chevalier, Dec 29 2015
STATUS
approved