OFFSET
0,3
COMMENTS
Number of compositions (ordered partitions) into partition numbers.
LINKS
Eric Weisstein's World of Mathematics, Partition Function P
FORMULA
G.f.: 1/(1 - Sum_{k>=1} x^p(k)).
EXAMPLE
a(4) = 7 because we have [3, 1], [2, 2], [2, 1, 1], [1, 3], [1, 2, 1], [1, 1, 2] and [1, 1, 1, 1].
MATHEMATICA
nmax = 38; CoefficientList[Series[1/(1 - Sum[x^PartitionsP[k], {k, 1, nmax}]), {x, 0, nmax}], x]
CROSSREFS
KEYWORD
nonn
AUTHOR
Ilya Gutkovskiy, Dec 30 2016
STATUS
approved