A013501 - OEIS

%I #11 Dec 14 2016 09:56:06

%S 1,-1,1,-2,9,-32,157,-828,5481,-35496,290649,-2290840,22092829,

%T -204459452,2273871485,-24119527604,303515669169,-3629239434576,

%U 50931449481777,-677485393669744,10484228007290613,-153504673218503140,2595681901243781013,-41471161060916985516,760471144497476539177,-13162910847523759863288

%N Expansion of e.g.f.: exp(sec(x)-exp(x))=1-x+1/2!*x^2-2/3!*x^3+9/4!*x^4-32/5!*x^5...

%p read transforms;

%p t1:=exp(sec(x)-exp(x)); #A013501

%p t2:=series(t1,x,30);

%p t3:=SERIESTOLISTMULT(%);

%t With[{nn=30},CoefficientList[Series[Exp[Sec[x]-Exp[x]],{x,0,nn}],x] Range[0,nn]!] (* _Harvey P. Dale_, Dec 14 2016 *)

%K sign

%O 0,4

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

%E More terms from _N. J. A. Sloane_, Dec 17 2011

%E Definition clarified by _Harvey P. Dale_, Dec 14 2016