%I A095025
%S A095025 1,1,2,1,1,1,3,1,1,1,1,1,2,0,2,1,0,1,2,0,1,1,1,1,0,2,1,1,3,1,3,0,1,0,0,
%T A095025 1,1,4,1,1,0,1,0,0,0,1,1,1,1,0,1,1,0,0,1,0,0,1,0,1,6,0,2,0,0,1,1,0,1,1,
%U A095025 1,1,1,0,0,0,0,1,1,1,1,1,1,0,0,0,1,1,1,0,0,0,1,0,0,1,1,0
%N A095025 Number of cyclic difference sets with n elements.
%C A095025 A (v,k,lambda) cyclic difference set is a subset D={d_1,d_2,...,d_k} 
               of the integers modulo v such that {1,2,...,v-1} can each be represented 
               as a difference (d_i-d_j) modulo v in exactly lambda different ways.
%H A095025 Dan Gordon, <a href="http://www.ccrwest.org/diffsets/diff_sets/">La Jolla 
               Difference Set Repository</a>
%H A095025 Len Baumert and Dan Gordon, <a href="http://www.ccrwest.org/diffsets/
               papers/">Papers on Difference Sets</a>
%H A095025 Dan Gordon, <a href="http://www.ccrwest.org/diffsets/ds_list.pdf">List 
               of Cyclic Difference Sets</a>
%e A095025 a(3)=1 corresponds to the (7,3,1) set {1,2,4}, a(4)=1 corresponds to 
               the (14,4,1) set {0,1,3,9}.
%e A095025 a(5)=2 because there are two cyclic difference sets of length 5: The 
               (v,k,lambda)=(11,5,2) set A095028={1,3,4,5,9} and the (21,5,1) set 
               A095029= {3,6,7,12,14}
%Y A095025 Cf. A095029-A095047 examples of cyclic difference set with k=5..20.
%Y A095025 Sequence in context: A128258 A104967 A098495 this_sequence A069897 A107682 
               A085476
%Y A095025 Adjacent sequences: A095022 A095023 A095024 this_sequence A095026 A095027 
               A095028
%K A095025 nonn
%O A095025 3,3
%A A095025 Hugo Pfoertner (hugo(AT)pfoertner.org), May 27 2004