OFFSET
0,2
LINKS
Vincenzo Librandi, Table of n, a(n) for n = 0..200
EXAMPLE
exp(sec(x)-sech(x)) = 1+2/2!*x^2+12/4!*x^4+242/6!*x^6+8512/8!*x^8...
MATHEMATICA
With[{nn=40}, Take[CoefficientList[Series[Exp[Sec[x]-Sech[x]], {x, 0, nn}], x]Range[0, nn]!, {1, -1, 2}]] (* Harvey P. Dale, Dec 23 2012 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Patrick Demichel (patrick.demichel(AT)hp.com)
EXTENSIONS
Confirmed by N. J. A. Sloane, Dec 17 2011
More terms from Harvey P. Dale, Dec 23 2012
STATUS
approved