A106881 Primes of the form x^2+xy+9y^2.

11, 29, 71, 79, 109, 149, 151, 179, 191, 211, 239, 281, 331, 359, 379, 389, 401, 421, 431, 449, 491, 499, 541, 569, 571, 599, 631, 641, 659, 701, 709, 739, 751, 809, 821, 911, 919, 991, 1009, 1019, 1031, 1051, 1061, 1129, 1171, 1201, 1229, 1289, 1381

Offset: 1

Author

T. D. Noe, May 09 2005

Keywords

• nonn
• easy

Comments

Discriminant=-35.

Also, primes of the form x^2-xy+9y^2, with x and y nonnegative.

Also, primes which are squares (mod 35). A subsequence of A191026. - M. F. Hasler, Jan 15 2016

Links

• Vincenzo Librandi and Ray Chandler, Table of n, a(n) for n = 1..10000 [First 1000 terms from Vincenzo Librandi]
• N. J. A. Sloane et al., Binary Quadratic Forms and OEIS (Index to related sequences, programs, references)

Crossrefs

Primes in A243178.

Programs

Mathematica

QuadPrimes2[1, -1, 9, 10000] (* see A106856 *)

PARI

select(p->issquare(Mod(p,35))&&isprime(p),[1..1000]) \\ M. F. Hasler, Jan 15 2016