%I #4 Feb 24 2012 12:51:15
%S 1,-4,80,-4384,451328,-74726784,18162914304,-6087614197760,
%T 2690808196562944,-1516485688823611392,1061352718471077658624,
%U -903110171035290053246976,918161695966849718656434176
%N sech(arctan(x)+tan(x))=1-4/2!*x^2+80/4!*x^4-4384/6!*x^6+451328/8!*x^8...
%K sign
%O 0,2
%A Patrick Demichel (patrick.demichel(AT)hp.com)