%I #3 Oct 01 2013 17:57:43
%S 0,2,0,3,4,4,5,6,5,6,0,7,6,8,8,0,9,8,9,10,10,8,9,0,11,11,12,10,12,11,
%T 12,13,10,13,12,14,14,14,12,15,13,15,14,16,15,16,13,14,16,15,17,17,13,
%U 14,18,18,16,18,17,0,19,15,18,19,17,19,20,18,20,15,20,17,0,21,20,21,19,21
%N z values corresponding to A087818.
%o (PARI) fourkp1(n) = { forstep(x=1,n,4, for(y=1,floor(sqrt(x)), z=x-y^2; if(issquare(z),print1(floor(sqrt(z))" "); break; ) ) ) }
%K nonn
%O 1,2
%A _Cino Hilliard_, Oct 06 2003