OFFSET
0,2
FORMULA
G.f. A(x) satisfies A(x) = A(x^3)/(1 - 3*x).
a(n) is divisible by 3 for n > 0.
PROG
(PARI) my(N=30, x='x+O('x^N)); Vec(1/prod(k=0, logint(N, 3), 1-3*x^3^k))
CROSSREFS
KEYWORD
nonn
AUTHOR
Seiichi Manyama, Jul 14 2024
STATUS
approved