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A124103
C(2*n,n)*stirling2(2*n,n).
0
1, 2, 42, 1800, 119070, 10716300, 1223054448, 169298088960, 27564503362110, 5162247741608100, 1093309327729799180, 258387397153927593552, 67415162325326493328560, 19247023513381472754036000
OFFSET
0,2
FORMULA
a(n) ~ 2^(4*n-1/2) * n^(n-1) / (Pi * sqrt(1-c) * exp(n) * (c*(2-c))^n), where c = -LambertW(-2*exp(-2)), see A226775 (= -c). - Vaclav Kotesovec, May 11 2014
MAPLE
a:=n->binomial(2*n, n)*stirling2(2*n, n): seq(a(n), n=0..16);
MATHEMATICA
Table[Binomial[2*n, n]*StirlingS2[2*n, n], {n, 0, 20}] (* Vaclav Kotesovec, May 11 2014 *)
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
Zerinvary Lajos, Nov 26 2006
STATUS
approved