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A009196 Expansion of exp(log(1+x)/cos(x)). 0
1, 1, 0, 3, 6, 15, 195, 126, 6860, 10581, 275955, 1581734, 11684442, 223836379, 423165561, 32439219242, 10301267912, 4976257880345, 4959730228167, 803695677341350, 3521551886934550, 131556027669677615 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,4

COMMENTS

Note that a(27) is negative. - Vaclav Kotesovec, Jan 24 2015

LINKS

Table of n, a(n) for n=0..21.

FORMULA

a(n) ~ n! * (-1)^n / (GAMMA(-1/cos(1)) * n^(1+1/cos(1))) * (1 - sin(1)*log(n)/((cos(1))^2*n)*(1+1/cos(1))). - Vaclav Kotesovec, Jan 24 2015

MATHEMATICA

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

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

CROSSREFS

Sequence in context: A013271 A013272 A013278 * A116613 A291803 A212977

Adjacent sequences:  A009193 A009194 A009195 * A009197 A009198 A009199

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 September 25 18:20 EDT 2017. Contains 292499 sequences.