A009746 Expansion of e.g.f. tan(x)*sinh(tan(x)), even powers only.

0, 2, 20, 438, 16680, 973034, 80252732, 8859646110, 1258403748432, 223202277906386, 48295209177888356, 12510350648500199814, 3820068667490198035320, 1357281805972469318509754

Offset

0,2

Links

G. C. Greubel, Table of n, a(n) for n = 0..239

Mathematica

With[{nmax = 50}, CoefficientList[Series[Tan[x]*Sinh[Tan[x]], {x, 0, nmax} ], x]*Range[0, nmax]!][[1 ;; ;; 2]] (* G. C. Greubel, Feb 12 2018 *)

Prog

(PARI) x='x+O('x^50); v=Vec(serlaplace(tan(x)*sinh(tan(x)))); concat([0], vector(#v\2, n, v[2*n-1])) \\ G. C. Greubel, Feb 12 2018

Crossrefs

Sequence in context: A058346 A165554 A366447 * A009749 A012533 A009160

Adjacent sequences: A009743 A009744 A009745 * A009747 A009748 A009749

Keyword

nonn

Author

R. H. Hardin

Extensions

Extended and signs tested by Olivier Gérard, Mar 15 1997

Status

approved