OFFSET
0,7
FORMULA
G.f.: Product_{k>=1} (1 + x^(2*prime(k)) / (1 - x^prime(k))).
EXAMPLE
a(10) = 3 because we have [5, 5], [3, 3, 2, 2] and [2, 2, 2, 2, 2].
MATHEMATICA
nmax = 70; CoefficientList[Series[Product[1 + x^(2 Prime[k])/(1 - x^Prime[k]), {k, 1, nmax}], {x, 0, nmax}], x]
CROSSREFS
KEYWORD
nonn
AUTHOR
Ilya Gutkovskiy, Nov 27 2020
STATUS
approved