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A009813 Expansion of tanh(tan(x))/cos(x). 0
1, 3, 17, 147, 3265, 248259, 25402769, 2697740307, 299763466753, 36321927229443, 5149754111041937, 933794260030934547, 223162280662322953153, 65749433548871560459971 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

LINKS

Table of n, a(n) for n=0..13.

MATHEMATICA

Tanh[ Tan[ x ] ]/Cos[ x ] (* Odd Part *)

CROSSREFS

Sequence in context: A052807 A080253 A234289 * A319946 A213507 A305471

Adjacent sequences:  A009810 A009811 A009812 * A009814 A009815 A009816

KEYWORD

nonn

AUTHOR

R. H. Hardin

EXTENSIONS

Extended and signs tested Mar 15 1997 by Olivier Gérard.

STATUS

approved

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Last modified February 19 07:51 EST 2019. Contains 320309 sequences. (Running on oeis4.)