%I A105974
%S A105974 0,0,1,9,109,2115,65011,3064929,215861689,22255521255,3305532624391,
%T A105974 698140838552949,207432475527926749,85925364190793529675,
%U A105974 49242162128564103516091,38783585510220344176524969
%N A105974 (A001035(n) - 1)/2 where A001035 is the number of partially ordered sets 
               ("posets") with n labeled elements.
%C A105974 Conjectures: a(n) is (pre)periodic modulo m for all m, the lengths of 
               the ending periods being given by 2*A000010(m) if m is a power of 
               2 and A000010(m) otherwise. A0000100 is Euler's totient function.
%Y A105974 Cf. A001035, A000010, A102818.
%Y A105974 Sequence in context: A166846 A058421 A128876 this_sequence A053912 A053894 
               A053904
%Y A105974 Adjacent sequences: A105971 A105972 A105973 this_sequence A105975 A105976 
               A105977
%K A105974 nonn
%O A105974 0,4
%A A105974 Gerald McGarvey (gerald.mcgarvey(AT)comcast.net), Apr 28 2005