login
This site is supported by donations to The OEIS Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A009122 Expansion of e.g.f. cosh(log(1+log(1+x))). 2
1, 0, 1, -6, 41, -335, 3229, -36036, 457932, -6534384, 103499016, -1802302128, 34227784920, -704076488232, 15595687319640, -370108332316992, 9368461983616128, -251958336139856448, 7174771808983995456 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,4

LINKS

G. C. Greubel, Table of n, a(n) for n = 0..250

FORMULA

a(n) ~ n! * (-1)^n * exp(n) / (2 * (exp(1)-1)^(n+1)). - Vaclav Kotesovec, Jan 22 2015

MATHEMATICA

CoefficientList[Series[(1 + (1 + Log[1 + x])^2)/(2*(1 + Log[1 + x])), {x, 0, 20}], x] * Range[0, 20]! (* Vaclav Kotesovec, Jan 22 2015 *)

PROG

(PARI) x='x+O('x^30); Vec(serlaplace(cosh(log(1+log(1+x))))) \\ G. C. Greubel, Jul 26 2018

(MAGMA) m:=30; R<x>:=PowerSeriesRing(Rationals(), m); b:=Coefficients(R!(Cosh(Log(1+Log(1+x))))); [Factorial(n-1)*b[n]: n in [1..m]]; // G. C. Greubel, Jul 26 2018

CROSSREFS

Twice the absolute values are in A052864.

Sequence in context: A083430 A005011 A187814 * A184140 A317410 A094869

Adjacent sequences:  A009119 A009120 A009121 * A009123 A009124 A009125

KEYWORD

sign,easy

AUTHOR

R. H. Hardin

EXTENSIONS

Extended with signs by Olivier Gérard, Mar 15 1997

STATUS

approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent | More pages
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified October 19 18:28 EDT 2018. Contains 316377 sequences. (Running on oeis4.)