OFFSET
0,106
COMMENTS
Number of partitions of n into distinct octagonal numbers (A000567).
LINKS
G. C. Greubel, Table of n, a(n) for n = 0..1000
Eric Weisstein's World of Mathematics, Octagonal Number
FORMULA
G.f.: Product_{k>=1} (1 + x^(k*(3*k-2))).
EXAMPLE
a(105) = 2 because we have [96, 8, 1] and [65, 40].
MATHEMATICA
nmax = 120; CoefficientList[Series[Product[1 + x^(k (3 k - 2)), {k, 1, nmax}], {x, 0, nmax}], x]
CROSSREFS
KEYWORD
nonn
AUTHOR
Ilya Gutkovskiy, Dec 09 2016
STATUS
approved