OFFSET
0,2
FORMULA
a(n) = [q^(3n+9)] Product_{j=1..n+3} (1-q^(2j))/(1-q) for n>=0.
PROG
(PARI) {a(n)=polcoeff(prod(j=1, n+3, (1-q^(2*j))/(1-q)), 3*n+9, q)}
CROSSREFS
KEYWORD
nonn
AUTHOR
Paul D. Hanna, Mar 12 2007
STATUS
approved