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A024297 Expansion of e.g.f. tan(x)*tan(tan(x))/2 (even powers only). 0
0, 1, 12, 344, 18496, 1617152, 209249792, 37538874368, 8908210487296, 2699849585000448, 1017035120794927104, 466006356701359898624, 255181639297776949919744, 164564302025304936925888512 (list; graph; refs; listen; history; text; internal format)
OFFSET
0,3
LINKS
MATHEMATICA
With[{nn=30}, Take[CoefficientList[Series[Tan[x]Tan[Tan[x]]/2, {x, 0, nn}], x] Range[ 0, nn]!, {1, -1, 2}]] (* Harvey P. Dale, Mar 18 2023 *)
PROG
(PARI) x='x+O('x^40); v=Vec(serlaplace(tan(x)*tan(tan(x))/2)); concat([0], vector(#v\2, n, v[2*n-1])) \\ Michel Marcus, Mar 13 2019
CROSSREFS
Cf. A009750.
Sequence in context: A231520 A305108 A027015 * A077296 A080481 A209425
KEYWORD
nonn
AUTHOR
EXTENSIONS
Extended and signs tested March 1997.
Name edited by Michel Marcus, Mar 13 2019
Prior Mathematica program replaced by Harvey P. Dale, Mar 18 2023
STATUS
approved

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Last modified May 23 06:14 EDT 2024. Contains 372760 sequences. (Running on oeis4.)