%I #4 Feb 24 2012 12:51:10
%S 1,3,-15,-1869,-88959,202499,974640433,190241481587,15481756625281,
%T -5564353308576125,-3510791865515349775,-961065703006847944525,
%U 92025876595389114977025,299254465799630697304777347
%N tanh(sec(x)*arctanh(x))=x+3/3!*x^3-15/5!*x^5-1869/7!*x^7-88959/9!*x^9...
%K sign
%O 0,2
%A Patrick Demichel (patrick.demichel(AT)hp.com)