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 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 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 LINKS G. C. Greubel, Table of n, a(n) for n = 1..242 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 Adjacent sequences:  A009755 A009756 A009757 * A009759 A009760 A009761 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

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Last modified February 20 14:56 EST 2019. Contains 320327 sequences. (Running on oeis4.)