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A339369
Number of partitions of n into an odd number of cubes.
2
0, 1, 0, 1, 0, 1, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 1, 2, 1, 2, 1, 2, 2, 2, 2, 3, 2, 3, 2, 3, 2, 4, 2, 4, 3, 4, 3, 4, 4, 4, 4, 5, 4, 5, 4, 5, 4, 6, 4, 6, 5, 6, 5, 7, 6, 7, 6, 8, 6, 8, 7, 8, 8, 9, 8, 9, 9, 9, 9, 10, 10, 11, 10, 12, 10, 12, 11, 12, 12, 14, 12, 14, 13, 14
OFFSET
0,18
FORMULA
G.f.: (1/2) * (Product_{k>=1} 1 / (1 - x^(k^3)) - Product_{k>=1} 1 / (1 + x^(k^3))).
a(n) = (A003108(n) - A292560(n)) / 2.
EXAMPLE
a(17) = 2 because we have [8, 8, 1] and [1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1].
MATHEMATICA
nmax = 85; CoefficientList[Series[(1/2) (Product[1/(1 - x^(k^3)), {k, 1, Floor[nmax^(1/3)] + 1}] - Product[1/(1 + x^(k^3)), {k, 1, Floor[nmax^(1/3)] + 1}]), {x, 0, nmax}], x]
CROSSREFS
KEYWORD
nonn
AUTHOR
Ilya Gutkovskiy, Dec 01 2020
STATUS
approved