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 A139507 #4 Jun 19 2014 15:30:14
%S A139507 29,59,199,239,281,349,419,431,439,521,571,631,719,811,821,919,941,
%T A139507 1009,1019,1021,1039,1069,1151,1231,1301,1321,1459,1579,1789,1831,
%U A139507 1861,1889,1949,1979,2029,2039,2089,2111,2141,2269,2311,2411,2441,2609,2659,2789
%N A139507 Primes of the form x^2 + 27x*y + y^2 for x and y nonnegative.
%H A139507 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 A139507 a = {}; w = 27; k = 1; Do[Do[If[PrimeQ[n^2 + w*n*m + k*m^2], AppendTo[a, n^2 + w*n*m + k*m^2]], {n, m, 400}], {m, 1, 400}]; Union[a] (*Artur Jasinski*)
%Y A139507 Cf. A139489, A007645, A068228, A007519, A033212, A033212, A107152, A107008, A033215, A107145, A139490, A139491.
%K A139507 nonn
%O A139507 1,1
%A A139507 _Artur Jasinski_, Apr 24 2008