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 A139506 #13 May 02 2024 19:04:39
%S A139506 193,337,457,673,1009,1033,1129,1201,1297,1801,1873,2017,2137,2377,
%T A139506 2473,2521,2689,2713,2857,3049,3217,3313,3361,3529,3697,3889,4057,
%U A139506 4153,4201,4561,4657,4729,4993,5209,5233,5569,5737,5881,6073,6217,6337,6553,6577
%N A139506 Primes of the form x^2 + 26x*y + y^2 for x and y nonnegative.
%C A139506 Also primes of the form x^2 + 168y^2. - _T. D. Noe_, Apr 29 2008
%C A139506 In base 12, the sequence is 141, 241, 321, 481, 701, 721, 7X1, 841, 901, 1061, 1101, 1201, 12X1, 1461, 1521, 1561, 1681, 16X1, 17X1, 1921, 1X41, 1E01, 1E41, 2061, 2181, 2301, 2421, 24X1, 2521, 2781, 2841, 28X1, 2X81, 3021, 3041, 3281, 33X1, 34X1, 3621, 3721, 3801, 3961, 3981, where X is 10 and E is 11. Moreover, the discriminant is 480. - _Walter Kehowski_, Jun 01 2008
%H A139506 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)
%F A139506 The primes are congruent to {1, 25, 121} (mod 168). - _T. D. Noe_, Apr 29 2008
%t A139506 a = {}; w = 26; 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]
%Y A139506 Cf. A139489, A007645, A068228, A007519, A033212, A107152, A107008, A033215, A107145, A139490, A139491.
%Y A139506 Cf. A139643.
%K A139506 nonn
%O A139506 1,1
%A A139506 _Artur Jasinski_, Apr 24 2008