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.

A049573 Primes p such that x^41 = 2 has a solution mod p.

Original entry on oeis.org

2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, 41, 43, 47, 53, 59, 61, 67, 71, 73, 79, 89, 97, 101, 103, 107, 109, 113, 127, 131, 137, 139, 149, 151, 157, 163, 167, 173, 179, 181, 191, 193, 197, 199, 211, 223, 227, 229, 233, 239, 241, 251, 257, 263, 269, 271, 277
Offset: 1

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Comments

Differs from A000040: 83 does not occur.

Examples

			0^41 == 2 (mod 2). 2^41 == 2 (mod 3). 2^41 == 2 (mod 5). 4^41 == 2 (mod 7). 2^41 == 2 (mod 11). 6^41 == 2 (mod 13). 2^41 == 2 (mod 17). 15^41 == 2 (mod 19). 13^41 == 2 (mod 23). 14^41 == 2 (mod 29). 2^41 == 2 (mod 31). 24^41 == 2 (mod 37). 2^41 == 2 (mod 41). 22^41 == 2 (mod 43). - _R. J. Mathar_, Jul 20 2025
		

Crossrefs

Cf. A000040, A059236 for primes not in this sequence.

Programs

  • Magma
    [p: p in PrimesUpTo(300) | exists(t){x : x in ResidueClassRing(p) | x^41 eq 2}]; // Vincenzo Librandi, Sep 14 2012
  • Mathematica
    ok[p_]:= Reduce[Mod[x^41 - 2, p] == 0, x, Integers] =!= False; Select[Prime[Range[100]], ok] (* Vincenzo Librandi, Sep 14 2012 *)