cp's OEIS Frontend

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.

Showing 1-4 of 4 results.

A191017 Primes with Kronecker symbol (p|14) = 1.

Original entry on oeis.org

3, 5, 13, 19, 23, 59, 61, 71, 79, 83, 101, 113, 127, 131, 137, 139, 151, 157, 173, 181, 191, 193, 227, 229, 233, 239, 251, 263, 269, 281, 283, 293, 307, 337, 349, 359, 397, 401, 419, 431, 449, 457, 461, 463, 467, 487, 509, 523, 563, 569, 587, 599, 617, 619
Offset: 1

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Author

T. D. Noe, May 24 2011

Keywords

Comments

Originally incorrectly named "Primes that are squares mod 14", which is sequence A045373. - M. F. Hasler, Jan 15 2016
Conjecture: primes congruent to {1, 3, 5, 9, 13, 15, 19, 23, 25, 27, 39, 45} mod 56. - Vincenzo Librandi, Jun 22 2016
From Jianing Song, Nov 21 2019: (Start)
Rational primes that decompose in the field Q(sqrt(-14)).
These are primes p such that either one of (a) p == 1, 2, 4 (mod 7), p == 1, 7 (mod 8) or (b) p == 3, 5, 6 (mod 7), p == 3, 5 (mod 8) holds. So the conjecture above is correct. (End)

Crossrefs

Programs

  • Magma
    [p: p in PrimesUpTo(619) | KroneckerSymbol(p, 14) eq 1]; // Vincenzo Librandi, Sep 11 2012
    
  • Mathematica
    Select[Prime[Range[200]], JacobiSymbol[#,14]==1&]
  • PARI
    is(p)=kronecker(p, 14)==1&&isprime(p) \\ Michel Marcus, Jun 23 2016 after A191032

Extensions

Definition corrected (following an observation by David Broadhurst) by M. F. Hasler, Jan 15 2016

A377177 Primes p such that -7/2 is a primitive root modulo p.

Original entry on oeis.org

11, 17, 29, 31, 37, 41, 43, 47, 73, 89, 103, 107, 109, 149, 167, 179, 197, 257, 277, 311, 313, 317, 347, 353, 367, 373, 383, 389, 409, 433, 479, 491, 499, 503, 521, 541, 557, 571, 577, 593, 601, 607, 647, 653, 659, 683, 701, 719, 727, 761, 769, 821, 839, 857, 883, 887, 907, 929, 937, 947, 983
Offset: 1

Views

Author

Jianing Song, Oct 18 2024

Keywords

Comments

If p is a term in this sequence, then -7/2 is not a square modulo p (i.e., p is in A191061).
Conjecture: this sequence has relative density equal to Artin's constant (A005596) with respect to the set of primes.

Crossrefs

Primes p such that +a/2 is a primitive root modulo p: A320384 (a=3), A377174 (a=5), A377176 (a=7), A377178 (a=9).
Primes p such that -a/2 is a primitive root modulo p: A377172 (a=3), A377175 (a=5), this sequence (a=7), A377179 (a=9).

Programs

A274504 Primes with Kronecker symbol (p|14) != 1.

Original entry on oeis.org

2, 7, 11, 17, 29, 31, 37, 41, 43, 47, 53, 67, 73, 89, 97, 103, 107, 109, 149, 163, 167, 179, 197, 199, 211, 223, 241, 257, 271, 277, 311, 313, 317, 331, 347, 353, 367, 373, 379, 383, 389, 409, 421, 433, 439, 443, 479, 491, 499, 503, 521, 541, 547, 557
Offset: 1

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Author

Vincenzo Librandi, Jun 29 2016

Keywords

Comments

Complement of A191017 in primes.
Conjecture: primes not congruent to (1, 3, 5, 9, 13, 15, 19, 23, 25, 27, 39, 45) mod 56.

Crossrefs

Programs

  • Magma
    [p: p in PrimesUpTo(619) | not KroneckerSymbol(p, 14) eq 1];
  • Mathematica
    Select[Prime[Range[200]], ! JacobiSymbol[#, 14] == 1 &]

A369863 Inert rational primes in the field Q(sqrt(-21)).

Original entry on oeis.org

13, 29, 43, 47, 53, 59, 61, 67, 73, 79, 83, 97, 113, 127, 131, 137, 149, 151, 157, 163, 167, 181, 197, 211, 227, 229, 233, 241, 251, 281, 311, 313, 317, 331, 349, 379, 383, 389, 397, 401, 409, 419, 433, 449, 463, 467, 479, 487, 499, 503, 547, 557, 563, 569, 571, 577, 587
Offset: 1

Views

Author

Dimitris Cardaris, Feb 03 2024

Keywords

Comments

Primes p such that Legendre(-21,p) = -1.

Crossrefs

Cf. inert rational primes in the imaginary quadratic field Q(sqrt(-d)) for the first squarefree positive integers d: A002145 (1), A003628 (2), A003627 (3), A003626 (5), A191059 (6), A003625 (7), A296925 (10), A191060 (11), A105885 (13), A191061 (14), A191062 (15), A296930 (17), A191063 (19), this sequence (21), A191064 (22), A191065 (23).

Programs

  • Mathematica
    Select[Range[3,600], PrimeQ[#] && JacobiSymbol[-21,#]==-1 &] (* Stefano Spezia, Feb 04 2024 *)
  • SageMath
    [p for p in prime_range(3, 600) if legendre_symbol(-21, p) == -1]
Showing 1-4 of 4 results.