OFFSET
0,8
EXAMPLE
a(9) = 2 because we have [7, 2] and [5, 4].
MATHEMATICA
Table[SeriesCoefficient[Product[(1 + Boole[Mod[n, k] != 0 && PrimePowerQ[k]] x^k), {k, 1, n}], {x, 0, n}], {n, 0, 73}]
CROSSREFS
KEYWORD
nonn
AUTHOR
Ilya Gutkovskiy, Mar 09 2018
STATUS
approved