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A013338 Expansion of e.g.f.: sec(exp(x)-sec(x))=1+1/2!*x^2+9/4!*x^4-20/5!*x^5+177/6!*x^6... 0

%I

%S 1,0,1,0,9,-20,177,-1260,7105,-99144,564049,-10278840,77134761,

%T -1412196188,15082747617,-257693157540,3771722331457,-62330454304272,

%U 1150241027577697,-19671866661968880,420212562193269513

%N Expansion of e.g.f.: sec(exp(x)-sec(x))=1+1/2!*x^2+9/4!*x^4-20/5!*x^5+177/6!*x^6...

%t With[{nn=20},CoefficientList[Series[Sec[Exp[x]-Sec[x]],{x,0,nn}],x] Range[ 0,nn]!] (* _Harvey P. Dale_, Feb 19 2020 *)

%K sign

%O 0,5

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

%E Definition clarified by _Harvey P. Dale_, Feb 19 2020

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Last modified July 29 22:13 EDT 2021. Contains 346346 sequences. (Running on oeis4.)