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 A106904 #21 Jan 15 2016 12:35:10 %S A106904 13,19,43,67,103,127,151,157,223,229,271,307,331,349,373,409,421,433, %T A106904 457,463,523,577,613,631,661,727,733,739,757,769,829,859,883,919,937, %U A106904 967,1021,1033,1039,1063,1069,1087,1123,1171,1237,1249,1279,1291,1327 %N A106904 Primes of the form x^2-xy+13y^2, with x and y nonnegative. %C A106904 Discriminant=-51. %C A106904 Also: Primes which are squares (mod 51). Differs from the subsequence A106903 (because x^2+xy+y^2 = (x+y)^2 - (x+y)y + y^2) from a(20) = 463 on, A106903(20) = 523. Terms which are not in A106903 are: 463, 631, 1033, 1039, 1279, 1291,... Up to 1279 these are also in A139643. Cf. also A191034. - _M. F. Hasler_, Jan 15 2016 %H A106904 Vincenzo Librandi and Ray Chandler, <a href="/A106904/b106904.txt">Table of n, a(n) for n = 1..10000</a> [First 1000 terms from Vincenzo Librandi] %H A106904 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 A106904 QuadPrimes2[1, -1, 13, 10000] (* see A106856 *) %o A106904 (PARI) select(p->issquare(Mod(p,51))&&isprime(p),[1..1500]) \\ See A106903 for alternative code. - _M. F. Hasler_, Jan 15 2016 %K A106904 nonn,easy %O A106904 1,1 %A A106904 _T. D. Noe_, May 09 2005