A013511 tanh(sec(x)-sech(x))=2/2!*x^2-118/6!*x^6-29998/10!*x^10...

2, -118, -29998, 611334362, -1141045350238, -231711278648170198, 7649386255065750464882, 1186434281262233535413422202, -294894146013123744005989421634238, -35339306131583165000023092663749603638, 51906656021441065578375756307601650588611602

Offset

0,1

Links

Table of n, a(n) for n=0..10.

Mathematica

With[{nn=50}, Take[CoefficientList[Series[Tanh[Sec[x]-Sech[x]], {x, 0, nn}], x] Range[0, nn]!, {3, -1, 4}]] (* Harvey P. Dale, Dec 29 2015 *)

Crossrefs

Sequence in context: A379549 A147774 A013470 * A013507 A013476 A103851

Adjacent sequences: A013508 A013509 A013510 * A013512 A013513 A013514

Keyword

sign

Author

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

Extensions

More terms from N. J. A. Sloane, Dec 17 2011

Status

approved