A191054 -id:A191054 - cp's OEIS frontend

A106989 Primes of the form x^2-xy+23y^2, with x and y nonnegative.

23, 29, 43, 53, 79, 107, 113, 127, 179, 191, 211, 233, 263, 277, 337, 347, 373, 389, 443, 491, 547, 569, 571, 599, 641, 653, 659, 673, 701, 751, 757, 809, 823, 883, 907, 911, 919, 953, 991, 1031, 1093, 1117, 1171, 1187, 1213, 1283, 1297, 1303, 1327

Offset: 1

T. D. Noe, May 09 2005

Discriminant=-91.

Also, primes that are squares (mod 91), or equivalently, with Legendre symbols (p|7) = (p|13) = 1. Included as subsequence in A191054 which are primes with Jacobi symbol (p|7*13) = 1, including also primes with (p|7) = (p|13) = -1. - David Broadhurst and M. F. Hasler, Jan 15 2016

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)

QuadPrimes2[1, -1, 23, 10000] (* see A106856 *)

is(p)=issquare(Mod(p,91))&&isprime(p) \\ M. F. Hasler, Jan 15 2016

A191085 Primes p that have Kronecker symbol (p|91) = -1.

Original entry on oeis.org

2, 3, 11, 17, 37, 61, 67, 71, 101, 103, 109, 131, 137, 139, 149, 151, 157, 163, 173, 181, 193, 197, 199, 239, 251, 257, 269, 281, 283, 311, 313, 317, 331, 359, 367, 379, 401, 419, 421, 431, 433, 439, 449, 457, 463, 467, 487, 499, 503, 521, 523, 541, 557, 563

Offset: 1

T. D. Noe, May 25 2011

Originally erroneously named "Primes that are not squares mod 91". - M. F. Hasler, Jan 18 2016

Vincenzo Librandi, Table of n, a(n) for n = 1..1000

Cf. A191054.

[p: p in PrimesUpTo(563) | JacobiSymbol(p, 91) eq -1]; // Vincenzo Librandi, Sep 11 2012

Select[Prime[Range[200]], JacobiSymbol[#,91]==-1&]

Definition corrected, following a suggestion from David Broadhurst, by M. F. Hasler, Jan 18 2016

cp's OEIS Frontend

A106989 Primes of the form x^2-xy+23y^2, with x and y nonnegative.

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