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.

A103309 Smallest prime primitive root of n that is less than n, or 0 if none exists.

Original entry on oeis.org

0, 0, 0, 2, 3, 2, 5, 3, 0, 2, 3, 2, 0, 2, 3, 0, 0, 3, 5, 2, 0, 0, 7, 5, 0, 2, 7, 2, 0, 2, 0, 3, 0, 0, 3, 0, 0, 2, 3, 0, 0, 7, 0, 3, 0, 0, 5, 5, 0, 3, 3, 0, 0, 2, 5, 0, 0, 0, 3, 2, 0, 2, 3, 0, 0, 0, 0, 2, 0, 0, 0, 7, 0, 5, 5, 0, 0, 0, 0, 3, 0, 2, 7, 2, 0, 0, 3, 0, 0, 3, 0, 0, 0, 0, 5, 0, 0, 5, 3, 0, 0, 2, 0, 5, 0
Offset: 0

Views

Author

Harry J. Smith, Jan 29 2005

Keywords

Comments

Differs from A046145 only for indices n = 2, 41, 109, 151, 229, ...; see A103335. - Jeppe Stig Nielsen, Mar 06 2020

Crossrefs

Programs

  • Maple
    F:= proc(n)
      local r;
      r:= numtheory:-primroot(n);
      while r::integer and not isprime(r) do
        r:= numtheory:-primroot(r,n);
      od:
      if r = FAIL then 0 else r fi
    end proc:
    seq(F(n),n=0..200); # Robert Israel, May 18 2015
  • Mathematica
    a[n_] := SelectFirst[PrimitiveRootList[n], PrimeQ[#] && # < n&] /. Missing["NotFound"] -> 0;
    Table[a[n], {n, 0, 104}] (* Jean-François Alcover, Nov 15 2017 *)

A103335 Numbers whose smallest primitive root (A046145) is not prime.

Original entry on oeis.org

1, 2, 41, 109, 151, 229, 251, 271, 313, 337, 362, 367, 409, 439, 542, 626, 674, 733, 761, 818, 878, 971, 991, 1021, 1031, 1069, 1289, 1297, 1303, 1429, 1471, 1489, 1681, 1759, 1783, 1789, 1811, 1871, 1873, 1879, 2062, 2137, 2342, 2411, 2441, 2551, 2594
Offset: 1

Views

Author

Harry J. Smith, Jan 31 2005

Keywords

Crossrefs

Programs

  • Maple
    filter:= proc(n)
      local r;
      r:= numtheory:-primroot(n);
      r <> FAIL and not isprime(r)
    end proc:
    filter(1):= true:
    select(filter, [$1..3000]); Robert Israel, Sep 08 2020
  • Mathematica
    L = {}; Do[ If[!PrimeQ[ Min[ Select[ Range[n], CoprimeQ[#, n] && MultiplicativeOrder[#, n] == CarmichaelLambda[n] &]]],
    L = Append[L, n]], {n, 1, 3000}]; L (* Jonathan Sondow, May 17 2017 *)

Extensions

Offset changed by Robert Israel, Sep 08 2020

A103336 Numbers whose largest primitive root (A046146) is not prime.

Original entry on oeis.org

1, 2, 11, 17, 19, 23, 29, 31, 37, 38, 41, 43, 47, 53, 58, 59, 62, 67, 71, 73, 74, 79, 81, 82, 83, 86, 89, 94, 97, 101, 107, 113, 118, 121, 122, 125, 127, 131, 134, 137, 139, 146, 149, 151, 157, 158, 162, 163, 167, 173, 178, 179, 191, 193, 194, 197, 211, 218, 223
Offset: 1

Views

Author

Harry J. Smith, Jan 31 2005

Keywords

Crossrefs

Programs

  • Mathematica
    Select[Range[250], #==1 || ((p = PrimitiveRootList[#]) != {} && ! PrimeQ[Max @ p]) &] (* Amiram Eldar, Sep 25 2021 *)

Extensions

Offset corrected by Amiram Eldar, Sep 25 2021

A103337 Smallest primitive root of numbers in sequence A103335.

Original entry on oeis.org

0, 1, 6, 6, 6, 6, 6, 6, 10, 10, 21, 6, 21, 15, 15, 15, 15, 6, 6, 21, 15, 6, 6, 10, 14, 6, 6, 10, 6, 6, 6, 14, 6, 6, 10, 6, 6, 14, 10, 6, 21, 10, 35, 6, 6, 6, 15, 6, 6, 10, 21, 14, 6, 33, 6, 6, 10, 6, 6, 6, 10, 6, 22, 15, 15, 6, 10, 12, 6, 15, 15, 10, 14, 21, 6, 15, 6, 6, 6, 6, 6, 6, 6, 10, 10, 6
Offset: 1

Views

Author

Harry J. Smith, Jan 31 2005

Keywords

Crossrefs

Programs

Extensions

Offset changed by Robert Israel, Sep 08 2020

A103338 Largest primitive root of numbers in sequence A103336.

Original entry on oeis.org

0, 1, 8, 14, 15, 21, 27, 24, 35, 33, 35, 34, 45, 51, 55, 56, 55, 63, 69, 68, 69, 77, 77, 75, 80, 77, 86, 91, 92, 99, 104, 110, 115, 117, 115, 123, 118, 128, 117, 134, 135, 141, 147, 146, 152, 153, 155, 159, 165, 171, 175, 176, 189, 188, 189, 195, 207, 207, 214
Offset: 1

Views

Author

Harry J. Smith, Jan 31 2005

Keywords

Crossrefs

Programs

  • Maple
    f:= proc(n) local m; uses NumberTheory;
      if n::odd then
        if NumberOfPrimeFactors(n,distinct) > 1 then return NULL fi;
      elif n mod 4 = 0 or NumberOfPrimeFactors(n,distinct) > 2 then return NULL
      fi;
      m:= PrimitiveRoot(n, ith=Totient(Totient(n)));
      if isprime(m) then NULL else m fi
    end proc:
    f(1):= 0:map(f, [$1..300]); # Robert Israel, Dec 01 2024

Extensions

Offset changed by Robert Israel, Dec 01 2024
Showing 1-5 of 5 results.