A013513 cosh(sec(x)-sech(x)) = 1+12/4!*x^4+8512/8!*x^8+34406592/12!*x^12...

1, 12, 8512, 34406592, 471749623552, 16325059994068992, 1187794482738667098112, 160833904474220565517811712, 37152672501146694986367085576192, 13716936936404675660073679524327063552, 7693299929324832174022888419623013572411392, 6292927164359183105695668653932580594051985702912

Offset

0,2

Links

Table of n, a(n) for n=0..11.

Mathematica

With[{nn=60}, Take[CoefficientList[Series[Cosh[Sec[x]-Sech[x]], {x, 0, nn}], x] Range[0, nn]!, {1, -1, 4}]] (* Harvey P. Dale, Mar 14 2017 *)

Crossrefs

Sequence in context: A009173 A012531 A013481 * A013480 A107254 A345679

Adjacent sequences: A013510 A013511 A013512 * A013514 A013515 A013516

Keyword

nonn

Author

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

Extensions

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

Status

approved