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 1-6 of 6 results.

A049544 Primes p such that x^12 = 2 has a solution mod p.

Original entry on oeis.org

2, 23, 31, 47, 71, 89, 113, 127, 167, 191, 223, 233, 239, 257, 263, 281, 311, 353, 359, 383, 431, 439, 479, 503, 593, 599, 601, 617, 647, 719, 727, 743, 839, 863, 881, 887, 911, 919, 983, 1031, 1049, 1097, 1103, 1151, 1193, 1217, 1223, 1289, 1319, 1327
Offset: 1

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Author

Keywords

Comments

Complement of A059264 relative to A000040. - Vincenzo Librandi, Sep 13 2012

Examples

			0^12 == 2 (mod 2). 2^12 == 2 (mod 23). 8^12 == 2 (mod 31). 4^12 == 2 (mod 47). 8^12 == 2 (mod 71). 2^12 == 2 (mod 89). 3^12 == 2 (mod 113). 8^12 == 2 (mod 127). - _R. J. Mathar_, Jul 20 2025
		

Crossrefs

Programs

  • Magma
    [p: p in PrimesUpTo(1400) | exists(t){x : x in ResidueClassRing(p) | x^12 eq 2}]; // Vincenzo Librandi, Sep 13 2012
  • Mathematica
    ok[p_]:= Reduce[Mod[x^12- 2, p] == 0, x, Integers]=!=False; Select[Prime[Range[200]], ok] (* Vincenzo Librandi, Sep 13 2012 *)

A059362 Primes p such that x^24 = 2 has no solution mod p.

Original entry on oeis.org

3, 5, 7, 11, 13, 17, 19, 29, 37, 41, 43, 53, 59, 61, 67, 73, 79, 83, 97, 101, 103, 107, 109, 113, 131, 137, 139, 149, 151, 157, 163, 173, 179, 181, 193, 197, 199, 211, 227, 229, 241, 251, 269, 271, 277, 281, 283, 293, 307, 313, 317, 331, 337, 347, 349, 353, 367
Offset: 1

Views

Author

Klaus Brockhaus, Jan 27 2001

Keywords

Comments

Complement of A049556 relative to A000040.
Coincides for the first 23 terms with sequence A059264 of primes p such that x^12 = 2 has no solution mod p (first divergence is at 113, cf. A059331).
Coincides for the first 161 terms with sequence A212376 of primes p such that x^48 = 2 has no solution mod p (first divergence is at 1217, cf. A059669).

Crossrefs

Programs

  • Magma
    [p: p in PrimesUpTo(400) | forall{x: x in ResidueClassRing(p) | x^24 ne 2}]; // Bruno Berselli, Sep 14 2012
  • Mathematica
    Select[Prime[Range[PrimePi[400]]], ! MemberQ[PowerMod[Range[#], 24, #], Mod[2, #]] &] (* Bruno Berselli, Sep 14 2012 *)
    ok[p_] := Reduce[Mod[x^24 - 2, p] == 0, x, Integers] == False; Select[Prime[Range[80]], ok] (* Vincenzo Librandi, Sep 20 2012 *)

A059668 Primes p such that x^36 = 2 has no solution mod p, but x^12 = 2 has a solution mod p.

Original entry on oeis.org

919, 1423, 1999, 2143, 2287, 2791, 4177, 4519, 4663, 5113, 5167, 6679, 6967, 8713, 9631, 9649, 9721, 11863, 12241, 12583, 12799, 13591, 16111, 17551, 18127, 20359, 20719, 21529, 21727, 21799, 22807, 23041, 23473, 23743, 23833, 23887, 23977
Offset: 1

Views

Author

Klaus Brockhaus, Feb 04 2001

Keywords

Crossrefs

Programs

  • Magma
    [p: p in PrimesUpTo(24000) | not exists{x: x in ResidueClassRing(p) | x^36 eq 2} and exists{x: x in ResidueClassRing(p) | x^12 eq 2}]; // Vincenzo Librandi, Sep 21 2012
  • Mathematica
    Select[Prime[Range[PrimePi[30000]]], ! MemberQ[PowerMod[Range[#], 36, #], Mod[2, #]]&& MemberQ[PowerMod[Range[#], 12, #], Mod[2, #]] &] (* Vincenzo Librandi, Sep 22 2013 *)

A070183 Primes p such that x^6 = 2 has a solution mod p, but x^(6^2) = 2 has no solution mod p.

Original entry on oeis.org

17, 41, 137, 401, 433, 449, 457, 521, 569, 641, 761, 809, 857, 919, 929, 953, 977, 1361, 1409, 1423, 1657, 1697, 1999, 2017, 2081, 2143, 2153, 2287, 2297, 2417, 2609, 2633, 2729, 2753, 2777, 2791, 2801, 2897, 2953, 3041, 3209, 3329, 3457, 3593, 3617
Offset: 1

Views

Author

Klaus Brockhaus, Apr 29 2002

Keywords

Crossrefs

Programs

  • Magma
    [p: p in PrimesUpTo(5000) | not exists{x: x in ResidueClassRing(p) | x^36 eq 2} and exists{x: x in ResidueClassRing(p) | x^6 eq 2}]; // Vincenzo Librandi, Sep 21 2012
    
  • Maple
    select(p -> isprime(p) and [msolve(x^6=2,p)]<>[] and [msolve(x^36=2,p)]=[] , [seq(i,i=3..10^4,2)]); # Robert Israel, May 13 2018
  • PARI
    forprime(p=2,3700,x=0; while(x
    				
  • PARI
    ok(p, r, k1, k2)={
        if (  Mod(r,p)^((p-1)/gcd(k1,p-1))!=1, return(0) );
        if (  Mod(r,p)^((p-1)/gcd(k2,p-1))==1, return(0) );
        return(1);
    }
    forprime(p=2,10^4, if (ok(p,2,6,6^2),print1(p,", ")));
    /* Joerg Arndt, Sep 21 2012 */
    
  • Python
    from itertools import count, islice
    from sympy import nextprime, is_nthpow_residue
    def A070183_gen(startvalue=2): # generator of terms >= startvalue
        p = max(nextprime(startvalue-1),2)
        while True:
            if is_nthpow_residue(2,6,p) and not is_nthpow_residue(2,36,p):
                yield p
            p = nextprime(p)
    A070183_list = list(islice(A070183_gen(),20)) # Chai Wah Wu, May 02 2024

A059331 Primes p such that x^24 = 2 has no solution mod p, but x^12 = 2 has a solution mod p.

Original entry on oeis.org

113, 281, 353, 593, 617, 1049, 1097, 1193, 1481, 1601, 1753, 1889, 2129, 2273, 2281, 2393, 2689, 3089, 3137, 3761, 3833, 4001, 4153, 4217, 4289, 4457, 4657, 4817, 4937, 5113, 5393, 5569, 6521, 6569, 6761, 7481, 7577, 7793, 7817, 7841, 8273, 8369, 8537
Offset: 1

Views

Author

Klaus Brockhaus, Jan 26 2001

Keywords

Crossrefs

Programs

  • Magma
    [p: p in PrimesUpTo(9000) | not exists{x: x in ResidueClassRing(p) | x^24 eq 2} and exists{x: x in ResidueClassRing(p) | x^12 eq 2}]; // Vincenzo Librandi, Sep 21 2012
  • Mathematica
    Select[Prime[Range[PrimePi[1000]]], !MemberQ[PowerMod[Range[#], 24, #], Mod[2, #]] && MemberQ[PowerMod[Range[#], 12, #], Mod[2, #]]&] (* Vincenzo Librandi, Sep 21 2013 *)

A216484 Primes p such that x^36 = 2 has no solution mod p.

Original entry on oeis.org

3, 5, 7, 11, 13, 17, 19, 29, 37, 41, 43, 53, 59, 61, 67, 73, 79, 83, 97, 101, 103, 107, 109, 131, 137, 139, 149, 151, 157, 163, 173, 179, 181, 193, 197, 199, 211, 227, 229, 241, 251, 269, 271, 277, 283, 293, 307, 313, 317, 331, 337, 347, 349, 367, 373, 379, 389
Offset: 1

Views

Author

Vincenzo Librandi, Sep 14 2012

Keywords

Comments

Complement of A049568 relative to A000040.
Different from A059264: 919, 1423, 1999, ... (see A059668) are terms of this sequence, but not of A059264. [Joerg Arndt, Sep 14 2012]
Coincides for the first 416 terms with the sequence of primes p such that x^108 = 2 has no solution mod p (first divergence is at 3947). [Bruno Berselli, Sep 14 2012]

Crossrefs

Cf. A059668 (primes p such that x^36 = 2 has no solution mod p, but x^12 = 2 has a solution mod p).

Programs

  • Magma
    [p: p in PrimesUpTo(400) | forall{x: x in ResidueClassRing(p) | x^36 ne 2}];
  • Mathematica
    ok[p_] := Reduce[Mod[x^36 - 2, p] == 0, x, Integers] == False; Select[Prime[Range[500]], ok]
    Select[Prime[Range[PrimePi[400]]], ! MemberQ[PowerMod[Range[#], 36, #], Mod[2, #]] &] (* Bruno Berselli, Sep 14 2012 *)
Showing 1-6 of 6 results.