OFFSET
0,2
MAPLE
A013514 := proc(n)
sec(sec(x)-sech(x)) ;
coeftayl( %, x=0, 4*n) ;
%*(4*n)! ;
end proc: # R. J. Mathar, Dec 16 2011
MATHEMATICA
With[{nn=40}, Take[CoefficientList[Series[Sec[Sec[x]-Sech[x]], {x, 0, nn}], x] Range[0, nn]!, {1, -1, 4}]] (* Harvey P. Dale, Dec 25 2017 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Patrick Demichel (patrick.demichel(AT)hp.com)
EXTENSIONS
More terms from N. J. A. Sloane, Dec 17 2011
STATUS
approved