A012648 - OEIS

A012648

exp(arcsinh(x)*arcsinh(x))=1+2/2!*x^2+4/4!*x^4+8/6!*x^6-240/8!*x^8...

1, 2, 4, 8, -240, 17952, -1948608, 295020672, -59798806272, 15680355451392, -5172616470494208, 2098138466506967040, -1026884688371863449600, 596895972998821973729280, -406569645650910092250562560

(list; graph; refs; listen; history; text; internal format)

OFFSET

0,2

LINKS

Table of n, a(n) for n=0..14.

FORMULA

a(n) ~ (-1)^(n+1) * Pi * 2^(2*n) *n^(2*n-1) / exp(2*n + (Pi^2)/4). - Vaclav Kotesovec, Nov 01 2013

MATHEMATICA

Table[n!*SeriesCoefficient[Exp[ArcSinh[x]*ArcSinh[x]], {x, 0, n}], {n, 0, 40, 2}] (* Vaclav Kotesovec, Nov 01 2013 *)

CROSSREFS

Sequence in context: A265595 A133036 A083147 * A130133 A033555 A130134

Adjacent sequences: A012645 A012646 A012647 * A012649 A012650 A012651

KEYWORD

sign

AUTHOR

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

STATUS

approved