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