A012043 cosh(sin(arcsinh(x))) = 1+1/2!*x^2-7/4!*x^4+121/6!*x^6-4271/8!*x^8...

1, 1, -7, 121, -4271, 262801, -25257079, 3510517193, -667413187039, 166471455235489, -52750545434135399, 20700581434214572441, -9854557734715140280207, 5594838313934367657655601

Offset

0,3

Links

Table of n, a(n) for n=0..13.

Formula

a(n) ~ (-1)^(n+1) * sin(sinh(Pi/2)) * cosh(Pi/2) * 2^(2*n) * n^(2*n-1) / exp(2*n). - Vaclav Kotesovec, Oct 30 2013

Mathematica

Table[n!*SeriesCoefficient[Cosh[Sin[ArcSinh[x]]], {x, 0, n}], {n, 0, 40, 2}] (* Vaclav Kotesovec, Oct 30 2013 *)

Crossrefs

Sequence in context: A012028 A279235 A094088 * A316730 A211103 A012103

Adjacent sequences: A012040 A012041 A012042 * A012044 A012045 A012046

Keyword

sign

Author

Patrick Demichel (patrick.demichel(AT)hp.com)

Status

approved