OFFSET
0,2
LINKS
Index entries for linear recurrences with constant coefficients, signature (2,-1,0,-2,-2,0,0,-1).
FORMULA
a(n) = 2*a(n-1) - a(n-2) - 2*a(n-4) - 2*a(n-5) - a(n-8).
a(n) = (1/2) * Sum_{k=0..floor(n/4)} (-1)^k * binomial(2*n-6*k+2,2*k+1).
PROG
(PARI) my(N=40, x='x+O('x^N)); Vec(1/((1-x+x^4)^2+4*x^5))
(PARI) a(n) = sum(k=0, n\4, (-1)^k*binomial(2*n-6*k+2, 2*k+1))/2;
CROSSREFS
KEYWORD
sign
AUTHOR
Seiichi Manyama, Aug 10 2024
STATUS
approved