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A012673 Expansion of tanh(tanh(x)*tan(x)). 2
2, -128, 12032, 365688832, -2002811158528, -67148259011330048, 3766780331499896963072, 40680896591210190242578432, -72225295511520670153244114157568 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,1

LINKS

Table of n, a(n) for n=0..8.

EXAMPLE

tanh(tanh(x)*tan(x))=2/2!*x^2-128/6!*x^6+12032/10!*x^10...

MATHEMATICA

Tanh[ Tanh[ x ]*Tan[ x ] ] (* [ x^(4n+2) ] *)

CROSSREFS

2 * A009823(n).

Sequence in context: A277757 A010367 A024344 * A086190 A024345 A012524

Adjacent sequences:  A012670 A012671 A012672 * A012674 A012675 A012676

KEYWORD

sign

AUTHOR

Patrick Demichel (patrick.demichel(AT)hp.com)

STATUS

approved

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Last modified October 26 05:15 EDT 2020. Contains 338027 sequences. (Running on oeis4.)