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%I #4 Mar 30 2012 16:45:52
%S 1,0,7,12,24,0,209,3561,5285,0,375372,2460490
%N (n,3,6) difference families over Z_n.
%D CRC Handbook of Combinatorial Designs, 1996, p. 285.
%K nonn,hard
%O 5,3
%A _N. J. A. Sloane_.