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A306733
Expansion of Sum_{k>=0} x^(k*(k+1)/2) * Product_{j=1..k} (1 + x^j)^j.
0
1, 1, 1, 1, 1, 2, 3, 2, 3, 5, 5, 8, 11, 11, 17, 19, 22, 33, 38, 50, 69, 82, 103, 133, 165, 201, 249, 319, 389, 492, 621, 765, 974, 1206, 1500, 1857, 2302, 2843, 3494, 4311, 5275, 6533, 8027, 9840, 12138, 14903, 18340, 22541, 27619, 33811, 41429, 50682, 61809, 75422, 91807
OFFSET
0,6
MATHEMATICA
nmax = 54; CoefficientList[Series[Sum[x^(k (k + 1)/2) Product[(1 + x^j)^j, {j, 1, k}], {k, 0, nmax}], {x, 0, nmax}], x]
CROSSREFS
KEYWORD
nonn
AUTHOR
Ilya Gutkovskiy, Mar 06 2019
STATUS
approved