This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A374276 #12 Jul 02 2024 10:19:44
%S A374276 1,1,0,0,1,1,0,0,0,1,0,1,0,0,0,0,1,0,0,1,1,0,0,0,0,1,0,0,0,1,0,1,0,0,
%T A374276 0,0,1,0,0,0,0,1,0,0,1,1,0,0,0,1,0,0,0,0,0,1,0,0,0,1,0,1,0,0,1,0,0,0,
%U A374276 0,0,0,1,0,0,0,0,1,0,0,1,1,1,0,0,0,0,0,0,0,1,0,0,0,0,0,1,0,0,0,1,1,1,0,0,0,0,0,0,0,1,0,0,0,0,0,0,1,0,0,0,0,2
%N A374276 Number of representations of n by the quadratic form x^2 + 3*x*y + y^2 with 0 <= x <= y.
%F A374276 a(A031363(n)) > 0.
%e A374276 121 = 0^2 + 3*0*11 + 11^2 = 3^2 + 3*3*7 + 7^2. So a(121) = 2.
%t A374276 a[n_]:=Module[{m=Floor[Sqrt[n]]},Sum[Sum[Boole[i^2+3i*j+j^2==n],{j,i,m}],{i,0,m}]]; Array[a,122,0] (* _Stefano Spezia_, Jul 02 2024 *)
%o A374276 (PARI) a(n) = my(m=sqrtint(n)); sum(i=0, m, sum(j=i, m, i^2+3*i*j+j^2==n));
%Y A374276 Cf. A031363, A088534, A374093, A374275.
%K A374276 nonn
%O A374276 0,122
%A A374276 _Seiichi Manyama_, Jul 02 2024