OFFSET
0,3
LINKS
Seiichi Manyama, Table of n, a(n) for n = 0..579
FORMULA
a(n) = Sum_{k=0..n} S2(k,n-k)*2^k where S2(n,k)=A048993(n,k);
a(n) = Sum_{k=0..floor(n/2)} S2(n-k,k)*2^(n-k).
MATHEMATICA
a[n_] := Sum[2^(n-k) * StirlingS2[n - k, k], {k, 0, Floor[n/2]}]; Array[a, 25, 0] (* Amiram Eldar, Apr 09 2022 *)
PROG
(PARI) a(n) = sum(k=0, n\2, 2^(n-k)*stirling(n-k, k, 2)); \\ Seiichi Manyama, Apr 08 2022
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
Paul Barry, May 19 2006
STATUS
approved