OFFSET
0,4
COMMENTS
Number of partitions of n into distinct partition numbers.
LINKS
Alois P. Heinz, Table of n, a(n) for n = 0..20000
M. Bernstein and N. J. A. Sloane, Some canonical sequences of integers, Linear Alg. Applications, 226-228 (1995), 57-72; erratum 320 (2000), 210. [Link to arXiv version]
M. Bernstein and N. J. A. Sloane, Some canonical sequences of integers, Linear Alg. Applications, 226-228 (1995), 57-72; erratum 320 (2000), 210. [Link to Lin. Alg. Applic. version together with omitted figures]
Eric Weisstein's World of Mathematics, Partition Function P, Partition Function Q
FORMULA
G.f.: Product_{k>=1} (1 + x^p(k)).
EXAMPLE
a(8) = 3 because we have [7, 1], [5, 3] and [5, 2, 1].
MATHEMATICA
nmax = 90; CoefficientList[Series[Product[(1 + x^PartitionsP[k]), {k, 1, nmax}], {x, 0, nmax}], x]
CROSSREFS
KEYWORD
nonn
AUTHOR
Ilya Gutkovskiy, Dec 30 2016
STATUS
approved