OFFSET
0,2
FORMULA
a(n) ~ n^(2*n) * c^(3*n) * 3^(5*n) / (sqrt(6*Pi*(c-1)*n) * exp(2*n) * (3*c-1)^(2*n)), where c = -LambertW(-1,-exp(-1/3)/3) = 2.237147027773716818...
MAPLE
seq(abs(Stirling1(3*n, n)), n=0..20);
MATHEMATICA
Table[Abs[StirlingS1[3*n, n]], {n, 0, 20}]
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Vaclav Kotesovec, May 20 2014
STATUS
approved