A102072 E.g.f. sec(arcsinh(x)) = cosec(arccosh(x)) (even powers only).

1, 1, 1, 25, -415, 35825, -3356575, 492769225, -96314333375, 24701457990625, -8006683308349375, 3204344303824405625, -1551453429875871169375, 893896220277392770140625, -604413346665043743464609375

Offset: 0

Author

Ralf Stephan, Dec 31 2004

Keywords

• sign

Examples

			sec(arcsinh(x)) = 1 + x^2/2 + x^4/4! + 25x^6/6! - 415x^8/8! +...
sech(arcsin(x)) = 1 - x^2/2 + x^4/4! - 25x^6/6! - 415x^8/8! -...
		

Programs

Mathematica

With[{nn=30},Take[CoefficientList[Series[Sec[ArcSinh[x]],{x,0,nn}],x] Range[0,nn]!,{1,-1,2}]] (* Harvey P. Dale, Aug 15 2016 *)