OFFSET
0,3
LINKS
Robert Israel, Table of n, a(n) for n = 0..345
FORMULA
a(n) = Sum_{k=0..n} (-1)^(n-k)*S(2*k,k).
a(n) ~ 2^(2*n) * n^(n-1/2) / (sqrt(2*Pi*(1-c)) * exp(n) * c^n * (2-c)^n), where c = -LambertW(-2*exp(-2)) = -A226775. - Vaclav Kotesovec, May 30 2025
MAPLE
seq(sum((-1)^(n-k)*combinat[stirling2](2*k, k), k=0..n), n=0..12);
# Alternative:
L:= [seq((-1)^n*Stirling2(2*n, n), n=0..50)]:
P:= ListTools:-PartialSums(L):
seq((-1)^(n+1)*P[n], n=1..51); # Robert Israel, Aug 25 2017
MATHEMATICA
Table[Sum[(-1)^(n-k)StirlingS2[2k, k], {k, 0, n}], {n, 0, 16}]
PROG
(Maxima) makelist(sum((-1)^(n-k)*stirling2(2*k, k), k, 0, n), n, 0, 12);
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Emanuele Munarini, Mar 12 2011
STATUS
approved
