A012082 - OEIS

%I #4 Feb 24 2012 12:50:40

%S 1,1,1,1,7681,1689601,390274561,113644876801,42729427952641,

%T 20428848924057601,12142755781873873921,8789483754515321088001,

%U 7614001483915573936550401,7778864404689826961021184001

%N tanh(arcsin(tan(x)))=x+1/3!*x^3+1/5!*x^5+1/7!*x^7+7681/9!*x^9...

%K nonn

%O 0,5

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