A012158 sech(tan(sinh(x)))=1-1/2!*x^2-7/4!*x^4-73/6!*x^6-239/8!*x^8...

1, -1, -7, -73, -239, 95311, 12793417, 1502683335, 172513245857, 17253776069663, 455220048522521, -596864160295290537, -305119961556198266191, -109834061252143977404561

Offset

0,3

Links

Harvey P. Dale, Table of n, a(n) for n = 0..100

Mathematica

With[{nn=30}, Take[CoefficientList[Series[Sech[Tan[Sinh[x]]], {x, 0, nn}], x] Range[0, nn]!, {1, -1, 2}]] (* Harvey P. Dale, Nov 18 2024 *)

Crossrefs

Sequence in context: A188465 A142053 A012049 * A139966 A175205 A373685

Adjacent sequences: A012155 A012156 A012157 * A012159 A012160 A012161

Keyword

sign

Author

Patrick Demichel

Extensions

More terms from N. J. A. Sloane, Aug 27 2006

Status

approved