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A024229 Expansion of e.g.f.: tanh(x)*sin(tan(x))/2 (even part). 2
0, 1, -2, 19, -1572, -24763, -5174758, -230357353, -45947071688, -3138700558071, -787255563055690, -40961532387015781, -13644908739614623724, 5015831039379054245197, 1910018990150165668013778, 1856616739480127236630886175, 892801482776535024911075390576 (list; graph; refs; listen; history; text; internal format)
OFFSET
0,3
LINKS
MATHEMATICA
nmax=200; expan=Series[Tanh[x]*Sin[Tan[x]]/2, {x, 0, 2*nmax}]; Join[{0}, Table[(2n)! Coefficient[expan, x^(2n)], {n, nmax}]] (* Stefano Spezia, Sep 17 2022 *)
PROG
(PARI) my(x='x+O('x^50), v=Vec(serlaplace(tanh(x)*sin(tan(x))/2))); concat(0, vector(#v\2, k, v[2*k-1])) \\ Michel Marcus, Sep 17 2022
CROSSREFS
Cf. A009834.
Sequence in context: A350933 A172028 A365050 * A094663 A274762 A091688
KEYWORD
sign
AUTHOR
EXTENSIONS
Extended with signs, Mar 1997
STATUS
approved

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Last modified July 14 01:31 EDT 2024. Contains 374290 sequences. (Running on oeis4.)