%I A011993
%S A011993 1,3,4,8,47,421,1550,13316,212968
%N A011993 (2n+1,3,3) difference families over Z_{2n+1}.
%D A011993 CRC Handbook of Combinatorial Designs, 1996, p. 285.
%Y A011993 Sequence in context: A155701 A119529 A096847 this_sequence A154714 A001695 
               A019676
%Y A011993 Adjacent sequences: A011990 A011991 A011992 this_sequence A011994 A011995 
               A011996
%K A011993 nonn,hard
%O A011993 2,2
%A A011993 N. J. A. Sloane (njas(AT)research.att.com).