OFFSET
1,2
LINKS
Colin Barker, Table of n, a(n) for n = 1..1000
Index entries for linear recurrences with constant coefficients, signature (1,2,-2,-1,1).
FORMULA
a(n) = (-3/4*(-1+(-1)^n)+(-5/2+3*(-1)^n)*n+5*n^2).
a(n) = a(n-1)+2*a(n-2)-2*a(n-3)-a(n-4)+a(n-5).
G.f.: -x*(12*x^3+7*x^2+20*x+1) / ((x-1)^3*(x+1)^2).
PROG
(PARI) Vec(-x*(12*x^3+7*x^2+20*x+1)/((x-1)^3*(x+1)^2) + O(x^100))
CROSSREFS
KEYWORD
nonn
AUTHOR
Colin Barker, Aug 12 2013
STATUS
approved