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A009427 Expansion of log(1+x)/cos(tan(x)). 1
0, 1, -1, 5, -12, 109, -405, 4913, -24976, 372633, -2419425, 42646845, -338219244, 6863821509, -64452230661, 1478191260393, -16062969072000, 410493211996977, -5072547848554017, 142840036992492789, -1979718755185227180 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,4

LINKS

Vaclav Kotesovec, Table of n, a(n) for n = 0..446

Vaclav Kotesovec, Graph - asymptotic ratio

FORMULA

a(n) ~ (n-1)! * (-1)^(n+1) / cos(tan(1)) * (1 + tan(tan(1)) / ((cos(1))^2*n)). - Vaclav Kotesovec, Jan 27 2015

MATHEMATICA

Log[ 1+x ]/Cos[ Tan[ x ] ]

CoefficientList[Series[Log[1 + x]*Sec[Tan[x]], {x, 0, 20}], x] * Range[0, 20]! (* Vaclav Kotesovec, Jan 24 2015 *)

CROSSREFS

Sequence in context: A009426 A304001 A009731 * A267271 A009754 A096314

Adjacent sequences:  A009424 A009425 A009426 * A009428 A009429 A009430

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 January 26 14:08 EST 2020. Contains 331280 sequences. (Running on oeis4.)