OFFSET
0,3
LINKS
Index entries for linear recurrences with constant coefficients, signature (0,2,2,-1,2,-1).
FORMULA
a(n) = 2*a(n-2) + 2*a(n-3) - a(n-4) + 2*a(n-5) - a(n-6).
a(n) = (1/2) * Sum_{k=0..floor(n/2)} binomial(2*k+2,2*n-4*k+1).
PROG
(PARI) my(N=40, x='x+O('x^N)); Vec(1/((1-x^2-x^3)^2-4*x^5))
(PARI) a(n) = sum(k=0, n\2, binomial(2*k+2, 2*n-4*k+1))/2;
CROSSREFS
KEYWORD
nonn
AUTHOR
Seiichi Manyama, Oct 02 2024
STATUS
approved