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A009731 Expansion of tan(x)*cosh(log(1+x)). 0
0, 1, 0, 5, -12, 96, -480, 3968, -29568, 283840, -2759040, 31139712, -369431040, 4852567552, -67622790144, 1018594276352, -16267048304640, 277008597516288, -4982377179119616, 94730142262034432, -1894021067538432000 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,4

LINKS

Table of n, a(n) for n=0..20.

FORMULA

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

MATHEMATICA

Tan[ x ]*Cosh[ Log[ 1+x ] ]

CoefficientList[Series[((1 + (1 + x)^2)*Tan[x])/(2*(1 + x)), {x, 0, 20}], x] * Range[0, 20]! (* Vaclav Kotesovec, Jan 23 2015 *)

CROSSREFS

Sequence in context: A249478 A009414 A009426 * A009427 A267271 A009754

Adjacent sequences:  A009728 A009729 A009730 * A009732 A009733 A009734

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 December 8 09:03 EST 2016. Contains 278906 sequences.