%I #22 Sep 08 2022 08:44:37
%S 1,0,0,3,-11,70,-354,2415,-15763,125172,-1002604,9222455,-86960631,
%T 905535618,-9647654054,109599211995,-1245410413895,14255558592040,
%U -147402624694104,1100681059753035,7361694753788285,-667740119513804610
%N Expansion of e.g.f.: cos(log(1+x))/cos(x).
%H G. C. Greubel, <a href="/A009025/b009025.txt">Table of n, a(n) for n = 0..250</a>
%t With[{nn=30},CoefficientList[Series[Cos[Log[1+x]]/Cos[x],{x,0,nn}], x]Range[0,nn]!] (* _Harvey P. Dale_, Dec 18 2011 *)
%o (PARI) x='x+O('x^30); Vec(serlaplace( cos(log(1+x))/cos(x) )) \\ _G. C. Greubel_, Jul 22 2018
%o (Magma) m:=30; R<x>:=PowerSeriesRing(Rationals(), m); b:=Coefficients(R!(Cos(Log(1+x))/Cos(x))); [Factorial(n-1)*b[n]: n in [1..m]]; // _G. C. Greubel_, Jul 22 2018
%K sign,easy
%O 0,4
%A _R. H. Hardin_
%E Extended with signs by _Olivier GĂ©rard_, Mar 15 1997
%E Definition clarified by _Harvey P. Dale_, Aug 15 2022