%I A012840
%S A012840 1,1,1,6,21,120,765,5376,46473,415104,4371225,48143744,594635613,
%T A012840 7784817664,110691178325,1673986906112,27018807872657,
%U A012840 462531126525952,8370279766396593,159859054841331712
%N A012840 exp(sec(x)*arctanh(x))=1+x+1/2!*x^2+6/3!*x^3+21/4!*x^4+120/5!*x^5...
%Y A012840 Sequence in context: A060843 A026650 A009253 this_sequence A013320 A056308 
               A081077
%Y A012840 Adjacent sequences: A012837 A012838 A012839 this_sequence A012841 A012842 
               A012843
%K A012840 nonn
%O A012840 0,4
%A A012840 Patrick Demichel (dml(AT)hpfrcu03.france.hp.com)