OFFSET
0,17
COMMENTS
Number of partitions of n such that the number of parts is a fourth power.
Also number of partitions of n such that the largest part is a fourth power.
FORMULA
a(18) = 3 because we have [18], [3, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1] and [2, 2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1] (see the first comment) or[16, 2], [16, 1, 1] and [1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1] (see the second comment).
MATHEMATICA
nmax = 57; CoefficientList[Series[Sum[x^(k^4)/Product[1 - x^j, {j, 1, k^4}], {k, 0, Floor[nmax^(1/4)] + 1}], {x, 0, nmax}], x]
CROSSREFS
KEYWORD
nonn
AUTHOR
Ilya Gutkovskiy, Dec 05 2020
STATUS
approved