%I #4 Mar 30 2012 18:37:43
%S 2,1,3,2,2,1,11,1,2,3,7,1,2,1,3,2,19,1,3,1,2,5,11,3,2,1,6,2,2,1,3,1,2,
%T 5,7,1,11,7,3,2,2,1,23,1,3,3,14,1,2,1,3,5,2,1,3,1,11,3,19,2,2,1,3,2,2,
%U 3,14,1,2,5,43,1,3,1,3,2,11,1,38,5,2,11,23,1,2,1,6,2,2,1,3,1,2,3,7,1,74,1
%N a(n) = smallest integer d such that a quadratic representation (2n+1)= x^2+ d*y^2 exists (x,y positive integers).
%e a(7)=11 because d=11 is the smallest d giving integer solutions x=2,y=1 in
%e (2*7+1)= x^2+d*y^2 = 2^2 + 11* 1^2 = 15.
%t << NumberTheory`NumberTheoryFunctions`; Table[First@Select[Range[100], !MatchQ[t=QuadraticRepresentation[ #, 2n+1], _QuadraticRepresentation]&, 1], {n, 1, 128}]
%K nonn
%O 1,1
%A _Wouter Meeussen_, Jun 20 2003