%I #5 Mar 30 2012 16:50:10
%S 1,2,5,16,56,120
%N Numbers n such that binomial(n,2) is in A027568.
%Y Cf. A027568.
%K nonn,fini,full
%O 1,2
%A _N. J. A. Sloane_, Sep 06 2008