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A009370 Expansion of log(1+tan(x))*cosh(x). 0
0, 1, -1, 7, -20, 125, -721, 5731, -49440, 505529, -5716921, 72560255, -1009426340, 15366052533, -253286287801, 4501151653979, -85717611666720, 1742059862631537, -37625735499057361, 860703388428813303 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,4

LINKS

Table of n, a(n) for n=0..19.

FORMULA

a(n) ~ (n-1)! * (-1)^(n+1) * (exp(-Pi/4) + exp(Pi/4)) * 2^(2*n-1) / Pi^n. - Vaclav Kotesovec, Jan 23 2015

MATHEMATICA

With[{nn=20}, CoefficientList[Series[Log[1+Tan[x]]*Cosh[x], {x, 0, nn}], x] Range[0, nn]!] (* Harvey P. Dale, May 25 2013 *)

CROSSREFS

Sequence in context: A265657 A298214 A299346 * A299091 A299873 A009372

Adjacent sequences:  A009367 A009368 A009369 * A009371 A009372 A009373

KEYWORD

sign,easy

AUTHOR

R. H. Hardin

EXTENSIONS

Extended with signs by Olivier Gérard, Mar 15 1997

STATUS

approved

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Last modified October 7 12:03 EDT 2022. Contains 357271 sequences. (Running on oeis4.)