A013440 - OEIS

%I #10 Aug 12 2015 16:22:41

%S 1,0,0,4,0,-8,160,992,-1792,-14464,484224,3391232,-30840832,

%T -175044608,7718963200,53080130560,-1315838558208,-6862446264320,

%U 426971596029952,2514483259473920,-136067874243248128

%N Expansion of e.g.f.: exp(tan(x)-arctan(x))=1+4/3!*x^3-8/5!*x^5+160/6!*x^6+992/7!*x^7...

%p A013440 := proc(n)

%p         exp(tan(x)-arctan(x)) ;

%p         coeftayl( %,x=0,n) ;

%p         %*n! ;

%p end proc: # _R. J. Mathar_, Dec 16 2011

%t With[{nn=20},CoefficientList[Series[Exp[Tan[x]-ArcTan[x]],{x,0,nn}],x] Range[0,nn]!] (* _Harvey P. Dale_, Aug 12 2015 *)

%K sign

%O 0,4

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

%E Definition clarified by _Harvey P. Dale_, Aug 12 2015