A013447 sec(tan(x)-arctan(x))=1+160/6!*x^6-1792/8!*x^8+484224/10!*x^10...

1, 0, 0, 160, -1792, 484224, -15071232, 6570936320, -461050544128, 285431558799360, -41198126773469184, 31834693166688370688, -8575650915562515595264, 7808988993818084822220800

Offset

0,4

Links

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

Mathematica

With[{nn=30}, Take[CoefficientList[Series[Sec[Tan[x]-ArcTan[x]], {x, 0, nn}], x] Range[0, nn]!, {1, -1, 2}]] (* Harvey P. Dale, Mar 19 2016 *)

Crossrefs

Sequence in context: A235655 A281404 A127409 * A013446 A013444 A013448

Adjacent sequences: A013444 A013445 A013446 * A013448 A013449 A013450

Keyword

sign

Author

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

Status

approved