

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
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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*n1])) \\ Michel Marcus, Mar 13 2019


CROSSREFS



KEYWORD

nonn


AUTHOR



EXTENSIONS

Extended and signs tested March 1997.


STATUS

approved



