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 1-5 of 5 results.

A059312 Primes p such that x^59 = 2 has no solution mod p.

Original entry on oeis.org

709, 827, 1063, 1181, 1889, 2243, 2833, 3187, 3541, 3659, 4013, 4603, 4721, 4957, 5783, 6373, 6491, 7789, 7907, 8969, 9323, 9677, 10267, 10739, 11093, 11329, 11801, 12037, 12391, 13099, 13217, 13807, 14633, 14869, 16993, 19471, 20297, 20533
Offset: 1

Views

Author

Klaus Brockhaus, Jan 25 2001

Keywords

Comments

This is not the same as "Primes congruent to 1 mod 59", A216315. The first missing number is A216315(27) = 11447. - Zak Seidov, Sep 03 2012
Complement of A216886 relative to A000040. - Vincenzo Librandi, Sep 20 2012

Crossrefs

Programs

  • Magma
    [p: p in PrimesUpTo(21000) | forall{x: x in ResidueClassRing(p) | x^59 ne 2}]; // Bruno Berselli, Sep 20 2012
  • Mathematica
    Select[Prime[Range[PrimePi[21000]]], ! MemberQ[PowerMod[Range[#], 59, #], Mod[2, #]] &] (* Bruno Berselli, Sep 20 2012 *)
    ok[p_] := Reduce[Mod[x^59 - 2, p] == 0, x, Integers] == False; Select[Prime[Range[2500]], ok]  (* Vincenzo Librandi, Sep 20 2012 *)

A059230 Primes p such that x^61 = 2 has no solution mod p.

Original entry on oeis.org

367, 733, 977, 1709, 1831, 2441, 3539, 4027, 4271, 4637, 4759, 5003, 5857, 6101, 6833, 7321, 7687, 8053, 8297, 8419, 8663, 9029, 9151, 9883, 10859, 12323, 12689, 13177, 13421, 14153, 14519, 15373, 15739, 16349, 17203, 17569, 18301, 18911
Offset: 1

Views

Author

Klaus Brockhaus, Jan 20 2001

Keywords

Comments

Presumably this is also Primes congruent to 1 mod 61 (A212378). - N. J. A. Sloane, Jul 11 2008
Complement of A216884 relative to A000040. - Vincenzo Librandi, Sep 20 2012
Regarding the first comment, the smallest counterexample is the prime 34039: 34039 == 1 (mod 61), but 1155^61 == 2 (mod 34039), therefore this prime is not in the sequence. - Bruno Berselli, Sep 20 2012

Crossrefs

Programs

  • Magma
    [p: p in PrimesUpTo(19000) | forall{x: x in ResidueClassRing(p) | x^61 ne 2} ]; // Vincenzo Librandi, Sep 20 2012
  • Mathematica
    ok[p_]:= Reduce[Mod[x^61 - 2, p] == 0, x, Integers] == False; Select[Prime[Range[5000]], ok] (* Vincenzo Librandi, Sep 20 2012 *)

A059225 Primes p such that x^31 = 2 has no solution mod p.

Original entry on oeis.org

311, 373, 1117, 1303, 1427, 1489, 1861, 2357, 2543, 2729, 2791, 3163, 3659, 3907, 4093, 4217, 4651, 5023, 5147, 5209, 5333, 5519, 5581, 5953, 6263, 6449, 6883, 7069, 7193, 7937, 8123, 8681, 8867, 8929, 9239, 9859, 10789, 11161, 11471, 11657, 11719
Offset: 1

Views

Author

Klaus Brockhaus, Jan 19 2001

Keywords

Comments

Complement of A216883 relative to A000040. - Vincenzo Librandi, Sep 20 2012

Crossrefs

Programs

  • Magma
    [p: p in PrimesUpTo(12500) | not exists{x : x in ResidueClassRing(p) | x^31 eq 2} ]; // Vincenzo Librandi, Sep 20 2012
  • Mathematica
     ok[p_]:= Reduce[Mod[x^31 - 2, p] == 0, x, Integers] == False; Select[Prime[Range[2000]], ok] (* Vincenzo Librandi, Sep 20 2012  *)

A059243 Primes p such that x^43 = 2 has no solution mod p.

Original entry on oeis.org

173, 431, 947, 1033, 1291, 1549, 1721, 1979, 2237, 2753, 3011, 3527, 3613, 4129, 4817, 4903, 5333, 5591, 5849, 6451, 6709, 6967, 7741, 8171, 8429, 9203, 9461, 9547, 9719, 10321, 10837, 11353, 11783, 12041, 13159, 13331, 13417, 13933, 14621
Offset: 1

Views

Author

Klaus Brockhaus, Jan 21 2001

Keywords

Comments

Complement of A058853 relative to A000040.

Crossrefs

Programs

  • Magma
    [p: p in PrimesUpTo(15000) | not exists{x : x in ResidueClassRing(p) | x^43 eq 2} ]; // Vincenzo Librandi, Sep 20 2012
  • Mathematica
    ok[p_]:= Reduce[Mod[x^43 - 2, p] == 0, x, Integers] == False; Select[Prime[Range[4000]], ok] (* Vincenzo Librandi, Sep 20 2012  *)

A059257 Primes p such that x^47 = 2 has no solution mod p.

Original entry on oeis.org

283, 659, 941, 1129, 1223, 1693, 1787, 2069, 2351, 2539, 2633, 3761, 4231, 4513, 4889, 5077, 5171, 5641, 5923, 6299, 6581, 6863, 7333, 8179, 8273, 8461, 8837, 9871, 10247, 10529, 11093, 11657, 11939, 12409, 12503, 12973, 13537, 13913, 14759
Offset: 1

Views

Author

Klaus Brockhaus, Jan 23 2001

Keywords

Comments

Presumably this is also Primes congruent to 1 mod 47. - N. J. A. Sloane, Jul 11 2008. Not so! The smallest counterexample is 26227: 26227 == 1 (mod 47), but 131^47 == 2 (mod 26227), therefore this prime is not in the sequence. - Bruno Berselli, Sep 12 2012
All terms are 1 mod 94. - Charles R Greathouse IV, Sep 13 2012
Complement of A216885 relative to A000040. - Vincenzo Librandi, Sep 20 2012

Crossrefs

Programs

  • Magma
    [p: p in PrimesUpTo(15000) | forall{x: x in ResidueClassRing(p) | x^47 ne 2}]; // Bruno Berselli, Sep 12 2012
    
  • Mathematica
    ok[p_]:= Reduce[Mod[x^47 - 2, p] == 0, x, Integers] == False; Select[Prime[Range[1800]], ok] (* Vincenzo Librandi, Sep 20 2012  *)
  • PARI
    select(p->!ispower(Mod(2,p),47),primes(3000)) \\ Charles R Greathouse IV, Sep 13 2012
Showing 1-5 of 5 results.