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 A228062 #6 Sep 13 2013 19:56:53
%S A228062 1,2,3,5,7,11,19,23,31,43,59,71,79,103,131,191,211,331,463
%N A228062 Numbers not expressible as a*b + b*c + a*c + 1 with positive numbers a, b, c.
%C A228062 Except for the first term, all terms are prime. There is at most one more term.
%t A228062 nn = 250; t = Select[Union[Flatten[Table[a*b + b*c + a*c + 1, {a, nn}, {b, a, nn}, {c, b, nn}]]], # <= 2*nn + 1 &]; Complement[Range[2*nn + 1], t]
%Y A228062 Cf. A025052.
%K A228062 nonn,fini
%O A228062 1,2
%A A228062 _T. D. Noe_, Sep 13 2013