login
A009758
Expansion of e.g.f. tan(x)/cos(tanh(x)) (odd powers only).
1
1, 5, 21, 377, 17161, 442925, 38819613, 3394928609, 307139569297, 50204583973973, 8330000263573413, 1585633516380134729, 416021432525199858841, 118441213090527475221629, 35638847609472720069131181, 15336745055032862739772925873
OFFSET
1,2
LINKS
MATHEMATICA
With[{nn=40}, Take[CoefficientList[Series[Tan[x]/Cos[Tanh[x]], {x, 0, nn}], x]*Range[0, nn-1]!, {2, -1, 2}]] (* Harvey P. Dale, Dec 08 2012 *)
PROG
(PARI) x='x+O('x^50); v=Vec(serlaplace(tan(x)/cos(tanh(x)))); vector((#v-1)\2 , n, v[2*n-1]) \\ G. C. Greubel, Feb 12 2018
CROSSREFS
Sequence in context: A101694 A006109 A009732 * A143503 A144779 A193324
KEYWORD
nonn
AUTHOR
EXTENSIONS
Extended and signs tested by Olivier Gérard, Mar 15 1997
More terms from Harvey P. Dale, Dec 08 2012
STATUS
approved