%I

%S 1,0,0,0,0,0,1,0,2,0,0,0,4,0,7,0,0,0,12,0,8,0,0,0,80,0,84,0,0,0,820,0,

%T 798,0,0,0,9508,0,11616,0,0,0,157340,0,139828,0,0,0,3027456,0,2353310

%N (n,3,1) difference families over Z_n.

%D CRC Handbook of Combinatorial Designs, 1996, p. 285.

%K nonn

%O 7,9

%A _N. J. A. Sloane_.