OFFSET
0,3
LINKS
Alois P. Heinz, Table of n, a(n) for n = 0..27
A. V. Sills and D. Zeilberger, Formulae for the number of partitions of n into at most m parts (using the quasi-polynomial ansatz) (arXiv:1108.4391 [math.CO])
FORMULA
a(n) = [x^(n^n)] Product_{j=1..n} 1/(1-x^j).
a(n) ~ exp(2*n) * n^(n*(n-3)) / (2*Pi). - Vaclav Kotesovec, May 25 2015
EXAMPLE
a(1) = 1: 1.
a(2) = 3: 22, 211, 1111.
a(3) = 75: 333333333, ..., 111111111111111111111111111.
MATHEMATICA
a[n_] := SeriesCoefficient[Product[1/(1 - x^j), {j, 1, n}], {x, 0, n^n}];
a[0] = 0;
Table[a[n], {n, 0, 5}] (* Jean-François Alcover, Nov 03 2018 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Alois P. Heinz, Feb 16 2014
STATUS
approved