OFFSET
0,1
COMMENTS
EXAMPLE
G.f.: T_1(q) = 3 + 30*q + 141*q^2 + 513*q^3 + 1815*q^4 + 5727*q^5 +...
Terms are divisible by 3:
A/3=[1,10,47,171,605,1909,5294,14139,36055,85277,195086,434322,...].
PROG
(PARI) {a(n)=local(L=sum(m=1, 3*n+1, 3*3^valuation(m, 3)*sumdiv(m, d, -(-1)^d*d)*x^m/m)+x*O(x^(3*n+1))); polcoeff(exp(L), 3*n+1)}
CROSSREFS
KEYWORD
nonn
AUTHOR
Paul D. Hanna, Jul 20 2009
STATUS
approved