OFFSET
0,7
MATHEMATICA
nmax = 67; CoefficientList[Series[Sum[x^(k^2) Product[(1 + j x^j), {j, 1, k}], {k, 0, nmax}], {x, 0, nmax}], x]
CROSSREFS
KEYWORD
nonn
AUTHOR
Ilya Gutkovskiy, Mar 16 2019
STATUS
approved