OFFSET
0,4
LINKS
Alois P. Heinz, Table of n, a(n) for n = 0..575
FORMULA
G.f.: Sum_{k>=0} pi(k)*x^k / Product_{j=1..k} (1-j*x).
E.g.f.: Sum_{k>=0} pi(k)*(exp(x)-1)^k/k!.
a(n) = Sum_{k=0..n} Stirling2(n,k)*pi(k).
MAPLE
b:= proc(n, m) option remember; `if`(n=0,
numtheory[pi](m), m*b(n-1, m)+b(n-1, m+1))
end:
a:= n-> b(n, 0):
seq(a(n), n=0..27);
CROSSREFS
KEYWORD
nonn
AUTHOR
Alois P. Heinz, Aug 13 2021
STATUS
approved