%I #13 Feb 03 2020 10:27:40
%S 1,2,3,2,1,2,1,2,5,0,2,1,1,0,1
%N Number of distinct parameter sets (v,k,lambda) for Abelian difference sets of order n = k-lambda with 1 <= lambda <= n-1.
%C a(17) is not known.
%D D. Jungnickel, Difference Sets, Chapter 7 of Jeffrey H. Dinitz and D. R. Stinson, Contemporary Design Theory, Wiley, 1992, see Appendix.
%e The 3 parameter sets for order 4 are (v,k,lambda) = (21,5,1), (16,6,2) and (15,7,3).
%K nonn,nice,hard,more
%O 2,2
%A _N. J. A. Sloane_, Jan 17 2000