%I #4 Feb 24 2012 12:50:36
%S 1,-1,1,47,897,26911,2176769,269558351,38463601409,6445724731199,
%T 1297792574780417,307585734223517551,82426762826906376833,
%U 23816926512873022989919,6844111898535212011277057
%N sech(sin(tan(x)))=1-1/2!*x^2+1/4!*x^4+47/6!*x^6+897/8!*x^8...
%K sign
%O 0,4
%A Patrick Demichel (patrick.demichel(AT)hp.com)