%I #5 Mar 30 2012 16:45:52
%S 8,0,27,0,0,0,20347,0
%N Number of (n,3,7) difference families over Z_n.
%D CRC Handbook of Combinatorial Designs, 1996, p. 285.
%K nonn,hard
%O 7,1
%A _N. J. A. Sloane_.
