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A009600 Expansion of e.g.f. sin(tan(x))*x/2 (even powers only). 1
1, 56, 5056, -8648704, -7517057024, 82066777604096, 27511745714323456, -8171138983967372345344, 74351622296124892534276096, 3458659437902679786800310910976, -174596051680041185684701426120392704, -1616689111713841897872270552294850822144 (list; graph; refs; listen; history; text; internal format)
OFFSET
0,2
LINKS
FORMULA
a(n) = (4*n+2)! * [x^(4*n+2)] sinh(sinh(x)*sin(x))/2.
MATHEMATICA
nmax = 50; coes = CoefficientList[Series[Sinh[Sinh[x]*Sin[x]]/2, {x, 0, 4*nmax + 2}], x]; a[n_] := coes[[4*n + 3]]*(4*n + 2)!; Table[a[n], {n, 0, nmax}] (* G. C. Greubel, Jan 30 2018 *)
CROSSREFS
Cf. A012528.
Sequence in context: A271139 A271140 A278324 * A278777 A202565 A213693
KEYWORD
sign
AUTHOR
EXTENSIONS
Extended with signs Mar 1997
STATUS
approved

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Last modified April 21 00:02 EDT 2024. Contains 371850 sequences. (Running on oeis4.)