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Revision History for A106863

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A106863

Primes of the form x^2+xy+5y^2.
(history; published version)

#22 by N. J. A. Sloane at Mon Dec 25 20:11:13 EST 2017

STATUS

editing

approved

#21 by N. J. A. Sloane at Mon Dec 25 20:11:10 EST 2017

COMMENTS

Also, primes p such that Legendre(-2,p) = 0 or 1. - N. J. A. Sloane, Dec 25 2017

STATUS

approved

editing

#20 by M. F. Hasler at Fri Jan 15 11:19:55 EST 2016

STATUS

editing

approved

#19 by M. F. Hasler at Fri Jan 15 11:19:26 EST 2016

COMMENTS

Also, primes which are a square (mod 19) (or, (mod 38) - cf. A191028). - M. F. Hasler, Jan 15 2016

PROG

(PARI) select(p->issquare(Mod(p, 19))&&isprime(p), [1..1000]) \\ M. F. Hasler, Jan 15 2016

STATUS

approved

editing

#18 by N. J. A. Sloane at Tue Aug 05 14:16:29 EDT 2014

MATHEMATICA

NON1234QuadPrimes2[1, -1, 5, 10000] (* see A106856 *)

Discussion

Tue Aug 05

14:16

OEIS Server: https://oeis.org/edit/global/2285

#17 by N. J. A. Sloane at Tue Aug 05 14:13:30 EDT 2014

MATHEMATICA

QuadPrimes2NON1234[1, -1, 5, 10000] (* see A106856 *)

Discussion

Tue Aug 05

14:13

OEIS Server: https://oeis.org/edit/global/2283

#16 by OEIS Server at Sat Jul 26 16:19:05 EDT 2014

LINKS

Vincenzo Librandi and Ray Chandler, <a href="/A106863/b106863_1.txt">Table of n, a(n) for n = 1..10000</a> [First 5000 terms from Vincenzo Librandi]

#15 by Ray Chandler at Sat Jul 26 16:19:05 EDT 2014

STATUS

editing

approved

Discussion

Sat Jul 26

16:19

OEIS Server: Installed new b-file as b106863.txt.  Old b-file is now b106863_1.txt.

#14 by Ray Chandler at Sat Jul 26 16:18:57 EDT 2014

LINKS

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)

#13 by Ray Chandler at Sat Jul 26 16:18:07 EDT 2014

LINKS

Vincenzo Librandi, <a href="/A106863/b106863.txt">Table of n, a(n) for n = 1..5000</a>

Vincenzo Librandi and Ray Chandler, <a href="/A106863/b106863_1.txt">Table of n, a(n) for n = 1..10000</a> [First 5000 terms from Vincenzo Librandi]

MATHEMATICA

QuadPrimes[1, -1, 5, 10000] (* see A106856 *) Note: the original QuadPrimes had a bug which could sometimes give wrong answers. This sequence should be checked (unless the coefficient of xy in the quadratic form is zero, in which case QuadPrimes gives correct answers). - N. J. A. Sloane, Jun 04 2014

QuadPrimes2[1, -1, 5, 10000] (* see A106856 *)

STATUS

approved

editing