A322856 Number of compositions (ordered partitions) of n into octagonal pyramidal numbers (A002414).
1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 12, 15, 19, 24, 30, 37, 45, 54, 64, 76, 91, 110, 135, 166, 204, 250, 305, 370, 447, 539, 650, 787, 956, 1164, 1419, 1730, 2107, 2562, 3110, 3770, 4569, 5540, 6723, 8166, 9926, 12070, 14677, 17841, 21675
Offset: 0
Keywords
Links
- Eric Weisstein's World of Mathematics, Pyramidal Number
- Index entries for sequences related to compositions
Programs
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Mathematica
nmax = 56; CoefficientList[Series[1/(1 - Sum[x^(k (k + 1) (2 k - 1)/2), {k, 1, nmax}]), {x, 0, nmax}], x]
Formula
G.f.: 1/(1 - Sum_{k>=1} x^(k*(k+1)*(2*k-1)/2)).