OFFSET
1,2
LINKS
Robert Price, Table of n, a(n) for n = 1..2000
FORMULA
a(n) = n * A000070(n-1).
G.f.: x*f'(x), where f(x) = (x/(1 - x))*Product_{k>=1} 1/(1 - x^k). - Ilya Gutkovskiy, Jun 08 2017
MATHEMATICA
Total /@ Table[n*PartitionsP[n-k], {n, 38}, {k, n}] // Flatten (* Robert Price, Jun 23 2020 *)
PROG
(PARI) a000070(n) = sum(k=0, n, numbpart(k));
for(n=1, 100, print1(n*a000070(n - 1), ", ")) \\ Indranil Ghosh, Jun 08 2017
(Python)
from sympy import npartitions as p
def a000070(n): return sum([p(k) for k in range(n + 1)])
def a(n): return n*a000070(n - 1) # Indranil Ghosh, Jun 08 2017
CROSSREFS
KEYWORD
nonn
AUTHOR
Omar E. Pol, Nov 28 2010
STATUS
approved