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 A243179 #8 Jun 20 2014 15:00:22
%S A243179 0,3,5,7,12,13,17,20,27,28,33,45,47,48,52,55,63,68,73,75,77,80,83,87,
%T A243179 97,103,105,108,112,117,125,132,143,145,147,153,157,167,173,175,180,
%U A243179 187,188,192,195,203,208,213,220,223,227,237,243,245,252,255,257,272,273,283,292,293,297,300,307,308,313,320,325,327,332,343,348,353,355,357,363,367
%N A243179 Numbers of the form 3x^2+xy+3y^2.
%C A243179 Discriminant -35.
%H A243179 N. J. A. Sloane et al., <a href="https://oeis.org/wiki/Binary_Quadratic_Forms_and_OEIS">Binary Quadratic Forms and OEIS</a> (Index to related sequences, programs, references)
%t A243179 ofTheFormQ[n_] := Reduce[n == 3*x^2 + x*y + 3*y^2, {x, y}, Integers] =!= False; Select[Range[0, 400], ofTheFormQ] (* _Jean-François Alcover_, Jun 04 2014 *)
%Y A243179 Primes: A106878.
%K A243179 nonn
%O A243179 1,2
%A A243179 _N. J. A. Sloane_, Jun 02 2014