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.

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A191834 Numbers n not divisible by 2 or 3 such that k^k == k+1 (mod n) has no nonzero solutions.

Original entry on oeis.org

205, 301, 455, 1015, 1025, 1085, 1435, 1505, 2107, 2255, 2275, 2485, 2665, 3185, 3311, 3485, 3895, 3913, 4715, 4823, 5005, 5075, 5117, 5125, 5425, 5467, 5719, 5915, 5945, 6355, 6923, 7105, 7175, 7525, 7585, 7595, 7735, 8405, 8645, 8729, 8815, 9331, 9635, 10045, 10465, 10535, 10865, 11137, 11165, 11275, 11375, 11935, 12095
Offset: 1

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Keywords

Comments

Values of A007310(n) for n such that A191833(n) = 0.
This sequence contains no primes. If p is a prime, and r is a primitive root of p, the numbers (r+j*p)^(r+j*p) for j = 1..p-1 include all residues of units mod p, and for p > 3, r+1 must be a unit.
The complete list of n such that k^k == k+1 (mod n) has no nonzero solutions is the union of A047229 and this sequence.

Crossrefs

Cf. A191833, A191835 (primitive elements).

Programs

  • Mathematica
    A191833[n_] := (For[m = 2*n + 2*Floor[n/2] - 1; k = 1, k <= m^2, k++, If[PowerMod[k, k, m] == Mod[k+1, m], Return[{k, m}]]]; {0, m}); Reap[For[j = 1; n = 1, n <= 5000, n++, {z, m} = A191833[n]; If[z == 0, Print["a(", j++, ") = ", m]; Sow[m]]]][[2, 1]] (* Jean-François Alcover, Sep 13 2013 *)

Extensions

Terms a(30) onward from Max Alekseyev, Sep 10 2013
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