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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
OFFSET
0,2
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
KEYWORD
sign
AUTHOR
Patrick Demichel (patrick.demichel(AT)hp.com)
EXTENSIONS
Prepended missing a(0)=0 from Vaclav Kotesovec, Nov 01 2013
STATUS
approved