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 A009073 Expansion of e.g.f. cos(tan(x))/cosh(x), even terms only. 1
 1, -2, 4, -128, 1296, -85600, 4372160, -148860416, 54261590272, 1474575037952, 1579094994228224, 145025202842173440, 87575771555229601792, 13290672132247757398016, 8077796113026531668901888 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,2 LINKS G. C. Greubel, Table of n, a(n) for n = 0..240 MATHEMATICA With[{nn=30}, Take[CoefficientList[Series[Cos[Tan[x]]/Cosh[x], {x, 0, nn}], x] Range[0, nn]!, {1, -1, 2}]] (* Harvey P. Dale, Feb 12 2015 *) PROG (PARI) x='x+O('x^50); v=Vec(serlaplace(cos(tan(x))/cosh(x))); vector(#v\2, n, v[2*n-1]) \\ G. C. Greubel, Jul 24 2018 CROSSREFS Sequence in context: A018493 A046035 A134710 * A326213 A369699 A012561 Adjacent sequences: A009070 A009071 A009072 * A009074 A009075 A009076 KEYWORD sign AUTHOR R. H. Hardin EXTENSIONS Extended with signs by Olivier Gérard, Mar 15 1997 Prior Mathematica program replaced by Harvey P. Dale, Feb 12 2015 STATUS approved

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Last modified September 8 22:43 EDT 2024. Contains 375759 sequences. (Running on oeis4.)