A012685 cosh(tanh(x)*arctan(x))=1+12/4!*x^4-480/6!*x^6+28560/8!*x^8...

1, 0, 12, -480, 28560, -2595840, 342910656, -62365675008, 14932846506240, -4548435497041920, 1716639310480919552, -786314410657025941504, 429828791337549223596032, -276479195899367035140833280

Offset

0,3

Links

Table of n, a(n) for n=0..13.

Mathematica

With[{nn=30}, Take[CoefficientList[Series[Cosh[Tanh[x]ArcTan[x]], {x, 0, nn}], x] Range[0, nn]!, {1, -1, 2}]] (* Harvey P. Dale, Aug 20 2024 *)

Crossrefs

Sequence in context: A012681 A009168 A012460 * A012465 A012394 A012686

Adjacent sequences: A012682 A012683 A012684 * A012686 A012687 A012688

Keyword

sign

Author

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

Status

approved