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A012649 sin(arcsinh(x)*arcsinh(x))=2/2!*x^2-8/4!*x^4+8/6!*x^6+2112/8!*x^8... 0
0, 2, -8, 8, 2112, -199008, 22569600, -3419806080, 685509888000, -177249701752320, 57657923420313600, -23084838758992066560, 11165823102677176074240, -6422018427189941047418880 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

LINKS

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

FORMULA

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

MATHEMATICA

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

CROSSREFS

Sequence in context: A009181 A009666 A012346 * A009627 A009677 A318605

Adjacent sequences:  A012646 A012647 A012648 * A012650 A012651 A012652

KEYWORD

sign

AUTHOR

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

EXTENSIONS

Prepended missing a(0)=0 from Vaclav Kotesovec, Nov 01 2013

STATUS

approved

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Last modified June 1 02:09 EDT 2020. Contains 334758 sequences. (Running on oeis4.)