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 A216513 #15 Jun 24 2017 12:11:45
%S A216513 1,1,0,0,1,0,1,1,0,1,1,0,0,0,0,1,1,0,0,0,0,0,1,0,1,2,0,0,1,0,0,1,0,1,
%T A216513 0,0,1,0,0,0,1,0,1,0,0,0,0,0,0,2,0,0,0,0,1,2,0,0,1,0,1,0,0,1,1,0,0,0,
%U A216513 0,0,2,0,0,1,0,0,0,0,0,1,0,1,0,0,0,0,0,1,1,0,1,0,0,0,0,0,1,1,0,0
%N A216513 Number of nonnegative integer solutions to the equation x^2 + 6*y^2 = n.
%t A216513 r[n_] := Reduce[x >= 0 && y >= 0 && x^2 + 6 y^2 == n, Integers];
%t A216513 a[n_] := Which[rn = r[n]; rn === False, 0, Head[rn] === And, 1, Head[rn] === Or, Length[rn], True, -1];
%t A216513 Table[a[n], {n, 0, 99}] (* _Jean-François Alcover_, Jun 24 2017 *)
%Y A216513 Cf. A002481.
%K A216513 nonn
%O A216513 0,26
%A A216513 _V. Raman_, Sep 08 2012
%E A216513 Verified by _N. J. A. Sloane_, Sep 10 2012
%E A216513 a(96) and a(97) corrected by _Jean-François Alcover_, Jun 24 2017