A012062 sech(sin(arctanh(x)))=1-1/2!*x^2+1/4!*x^4-1/6!*x^6+449/8!*x^8...

1, -1, 1, -1, 449, 45119, 6456385, 1205597119, 290952557185, 88525830844799, 33241403103347585, 15120239602445366399, 8199386238595549354561, 5228782379279703730965439, 3875091407041220683147290049

Offset

0,5

Links

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

Mathematica

With[{nn=30}, Take[CoefficientList[Series[Sech[Sin[ArcTanh[x]]], {x, 0, nn}], x] Range[0, nn]!, {1, -1, 2}]] (* Harvey P. Dale, Sep 15 2013 *)

Crossrefs

Sequence in context: A201182 A012169 A093402 * A339978 A351947 A079659

Adjacent sequences: A012059 A012060 A012061 * A012063 A012064 A012065

Keyword

sign

Author

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

Status

approved