OFFSET
0,4
LINKS
Index entries for linear recurrences with constant coefficients, signature (0,0,2,2,0,-1,2,-1).
FORMULA
a(n) = 2*a(n-3) + 2*a(n-4) - a(n-6) + 2*a(n-7) - a(n-8).
a(n) = Sum_{k=0..floor(n/3)} binomial(2*k+1,2*n-6*k+1).
PROG
(PARI) my(N=50, x='x+O('x^N)); Vec((1+x^3-x^4)/((1+x^3-x^4)^2-4*x^3))
(PARI) a(n) = sum(k=0, n\3, binomial(2*k+1, 2*n-6*k+1));
CROSSREFS
KEYWORD
nonn
AUTHOR
Seiichi Manyama, Oct 03 2024
STATUS
approved