OFFSET
15,3
FORMULA
G.f.: Sum_{k>=5} x^(k*(k + 1)/2) / Product_{j=1..k} (1 - x^j).
MATHEMATICA
nmax = 65; CoefficientList[Series[Sum[x^(k (k + 1)/2)/Product[(1 - x^j), {j, 1, k}], {k, 5, nmax}], {x, 0, nmax}], x] // Drop[#, 15] &
CROSSREFS
KEYWORD
nonn
AUTHOR
Ilya Gutkovskiy, Sep 07 2021
STATUS
approved