OFFSET
0,2
LINKS
G. C. Greubel, Table of n, a(n) for n = 0..235
FORMULA
a(n) = Sum_{m=1..n} (Sum_{k=0..2*n-2*m} (binomial(k+2*m-1, 2*m-1)*(k+2*m)!*(-1)^(k)*2^(2*n-2*m-k)*stirling2(2*n, k+2*m))/m!). - Vladimir Kruchinin, Jun 06 2011
MATHEMATICA
nmax = 20; Table[(CoefficientList[Series[Exp[Tanh[x]^2], {x, 0, 2*nmax}], x] * Range[0, 2*nmax]!)[[k]], {k, 1, 2*nmax, 2}] (* Vaclav Kotesovec, May 27 2022 *)
With[{nn=30}, Take[CoefficientList[Series[Exp[Tanh[x]^2], {x, 0, nn}], x] Range[0, nn]!, {1, -1, 2}]] (* Harvey P. Dale, Apr 08 2023 *)
PROG
(Maxima) a(n):=sum(sum(binomial(k+2*m-1, 2*m-1)*(k+2*m)!*(-1)^(k)*2^(2*n-2*m-k)*stirling2(2*n, k+2*m), k, 0, 2*n-2*m)/m!, m, 1, n); /* Vladimir Kruchinin, Jun 06 2011 */
(PARI) x = 'x + O(x^50); select(x->x, Vec(serlaplace(exp(tanh(x)^2)))) \\ Michel Marcus, Apr 01 2017
CROSSREFS
KEYWORD
sign
AUTHOR
EXTENSIONS
Extended with signs by Olivier Gérard, Mar 15 1997
STATUS
approved