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A012162
tan(tan(arcsinh(x)))=x+3/3!*x^3+41/5!*x^5+1187/7!*x^7+62129/9!*x^9...
1
1, 3, 41, 1187, 62129, 4782467, 547167193, 80119022947, 16118331113441, 3804780451118851, 1198259782941477641, 411098266056364045603, 189240360206280390564241, 87405020278156979563746947
OFFSET
0,2
COMMENTS
Note that a(25) is negative. - Vaclav Kotesovec, Feb 06 2015
LINKS
MATHEMATICA
With[{nn=30}, Take[CoefficientList[Series[Tan[Tan[ArcSinh[x]]], {x, 0, nn}], x] Range[0, nn-1]!, {2, -1, 2}]] (* Harvey P. Dale, Oct 21 2014 *)
CROSSREFS
Sequence in context: A241704 A181675 A012053 * A012225 A012129 A012035
KEYWORD
sign
AUTHOR
Patrick Demichel (patrick.demichel(AT)hp.com)
STATUS
approved