The On-Line Encyclopedia of Integer Sequences (OEIS)

Revision History for A009399

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A009399

Expansion of log(1+tanh(x)*x).
(history; published version)

#17 by Vaclav Kotesovec at Thu Dec 21 17:29:12 EST 2017

STATUS

editing

#16 by Vaclav Kotesovec at Thu Dec 21 17:27:24 EST 2017

CROSSREFS

Cf. A069855, A085984.

#15 by Vaclav Kotesovec at Thu Dec 21 17:22:50 EST 2017

CROSSREFS

#14 by Vaclav Kotesovec at Thu Dec 21 17:21:43 EST 2017

FORMULA

a(n) ~ -(-1)^n * sqrt(Pi) * 2^(2*n + 1) * n^(2*n - 1/2) / (r^(2*n) * exp(2*n)), where r = 0.8603335890193797624838934241376623334118843632... is the root of the equation r * tan(r) = 1. - Vaclav Kotesovec, Dec 21 2017

#13 by Vaclav Kotesovec at Thu Dec 21 17:20:33 EST 2017

FORMULA

STATUS

approved

#12 by Harvey P. Dale at Mon Jun 13 17:34:27 EDT 2016

STATUS

editing

#11 by Harvey P. Dale at Mon Jun 13 17:34:23 EDT 2016

MATHEMATICA

Log[ 1+Tanh[ x ]*x ] (* Even Part *)

EXTENSIONS

STATUS

approved

#10 by Jon E. Schoenfield at Mon Jun 22 22:30:27 EDT 2015

STATUS

editing

#9 by Jon E. Schoenfield at Mon Jun 22 22:30:26 EDT 2015

NAME

Expansion of ln(1+tanh(x).x).

EXTENSIONS

Extended with signs Mar 15 1997 by Olivier Gérard.

STATUS

approved

#8 by N. J. A. Sloane at Mon Jan 27 09:12:50 EST 2014

EXTENSIONS

Extended with signs Mar 15 1997 by Olivier Gerard.

Discussion

Mon Jan 27

09:12

OEIS Server: https://oeis.org/edit/global/2111