OFFSET
0,4
LINKS
Index entries for linear recurrences with constant coefficients, signature (1,0,3,0,0,-3,0,0,1).
FORMULA
G.f.: 1 / (1 - x^3 - x/(1 - x^3)^2).
a(n) = a(n-1) + 3*a(n-3) - 3*a(n-6) + a(n-9) for n > 8.
PROG
(PARI) a(n) = sum(k=0, n\3, binomial(3*n-8*k, k));
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Seiichi Manyama, Jun 12 2024
STATUS
approved