

A009754


Expansion of e.g.f. tan(x)/cos(log(1+x)).


1



0, 1, 0, 5, 12, 116, 720, 7048, 67648, 789124, 9839520, 137625652, 2079277200, 34199202272, 604204537664, 11450703405872, 231315430836480, 4966162863717008, 112867805704455936, 2707812372195278800, 68377223974957136320, 1812971997782789669056
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OFFSET

0,4


LINKS

G. C. Greubel, Table of n, a(n) for n = 0..430


FORMULA

a(n) ~ n! * (1)^(n+1) * tan(1exp(Pi/2)) / ((exp(Pi/2)1) * (1exp(Pi/2))^n).  Vaclav Kotesovec, Jan 24 2015


MATHEMATICA

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


PROG

(PARI) x='x+O('x^30); concat([0], Vec(serlaplace(tan(x)/cos(log(1+x))))) \\ G. C. Greubel, Feb 12 2018


CROSSREFS

Sequence in context: A009731 A009427 A267271 * A096314 A323565 A195538
Adjacent sequences: A009751 A009752 A009753 * A009755 A009756 A009757


KEYWORD

sign,easy


AUTHOR

R. H. Hardin


EXTENSIONS

Extended with signs by Olivier Gérard, Mar 15 1997


STATUS

approved



