%I A028312
%S A028312 3,9,11,15,19,21,27,33,39
%N A028312 Odd numbers n such that {1..n-1} cannot be partitioned into disjoint 
               sets I, J such that 2I = -J (mod n) and I, J are unions of cyclotomic 
               cosets mod n.
%D A028312 F. J. MacWilliams, A. M. Odlyzko, N. J. A. Sloane and H. N. Ward, Self-Dual 
               Codes over GF(4), J. Combin. Theory, A 25 288-318 1978.
%Y A028312 Cf. A028311.
%Y A028312 Sequence in context: A075720 A106373 A059326 this_sequence A074486 A131861 
               A131859
%Y A028312 Adjacent sequences: A028309 A028310 A028311 this_sequence A028313 A028314 
               A028315
%K A028312 nonn,more
%O A028312 1,1
%A A028312 N. J. A. Sloane (njas(AT)research.att.com).