OFFSET
1,2
COMMENTS
FORMULA
G.f.: Sum_{i>=1} x^(i^3)/(1 - x^(i^3)) / Product_{j>=1} (1 - x^(j^3)).
EXAMPLE
a(9) = 11 because we have [8, 1], [1, 1, 1, 1, 1, 1, 1, 1, 1] and 2 + 9 = 11.
MATHEMATICA
nmax = 70; Rest[CoefficientList[Series[Sum[x^i^3/(1 - x^i^3), {i, 1, nmax}]/Product[1 - x^j^3, {j, 1, nmax}], {x, 0, nmax}], x]]
CROSSREFS
KEYWORD
nonn
AUTHOR
Ilya Gutkovskiy, Jan 25 2017
STATUS
approved