A012466 E.g.f. sec(arctan(x)^2) (even powers only).

1, 0, 12, -480, 37968, -4773120, 878319552, -222512349696, 74262725323008, -31578556041732096, 16666719859336276992, -10690478515516973015040, 8190555666463900906475520, -7387658525325188387856384000

Offset

0,3

Links

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

Example

sec(arctan(x)^2) = =1+12/4!*x^4-480/6!*x^6+37968/8!*x^8+-...

Mathematica

With[{nn=30}, Take[CoefficientList[Series[Sec[ArcTan[x]^2], {x, 0, nn}], x]Range[0, nn]!, {1, -1, 2}]] (* Harvey P. Dale, Jan 12 2013 *)

Crossrefs

Sequence in context: A012465 A012394 A012686 * A344113 A229634 A196704

Adjacent sequences: A012463 A012464 A012465 * A012467 A012468 A012469

Keyword

sign

Author

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

Status

approved