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A012145 sech(arcsin(arctanh(x)))=1-1/2!*x^2-7/4!*x^4-169/6!*x^6-9199/8!*x^8... 0
1, -1, -7, -169, -9199, -915441, -146524599, -34565815257, -11286151088991, -4868161148587617, -2677533017865604839, -1826930427561513127305, -1513046625847449915823695, -1494316021415982844933350225 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,3

LINKS

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

CROSSREFS

Sequence in context: A162131 A258299 A012067 * A005019 A172027 A113562

Adjacent sequences:  A012142 A012143 A012144 * A012146 A012147 A012148

KEYWORD

sign

AUTHOR

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

STATUS

approved

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Last modified October 18 08:58 EDT 2021. Contains 348067 sequences. (Running on oeis4.)