A105877 -id:A105877 - cp's OEIS frontend

A167801 Numbers with primitive root -5.

2, 4, 11, 17, 19, 22, 34, 37, 38, 53, 59, 73, 74, 79, 97, 106, 113, 118, 121, 131, 137, 139, 146, 151, 157, 158, 173, 179, 193, 194, 197, 226, 233, 239, 242, 257, 262, 274, 277, 278, 289, 293, 302, 311, 314, 317, 331, 346, 353, 358, 359, 361, 373, 386, 394, 397

Offset: 1

T. D. Noe, Nov 12 2009

nonn

Vincenzo Librandi, Table of n, a(n) for n = 1..1000

Cf. A105877 (primes with primitive root -5)

pr=-5; Select[Range[2,2000], MultiplicativeOrder[pr,# ] == EulerPhi[ # ] &]

A380532 a(n) is the multiplicative order of -5 modulo prime(n); a(3) = 0 for completion.

Original entry on oeis.org

1, 1, 0, 3, 10, 4, 16, 18, 11, 7, 6, 36, 20, 21, 23, 52, 58, 15, 11, 10, 72, 78, 41, 44, 96, 50, 51, 53, 54, 112, 21, 130, 136, 138, 74, 150, 156, 27, 83, 172, 178, 30, 38, 192, 196, 66, 70, 111, 113, 57, 232, 238, 40, 50, 256, 131, 134, 54, 276, 140

Offset: 1

Jianing Song, Jun 27 2025

Jianing Song, Table of n, a(n) for n = 1..10000

Cf. A105877 (primes having primitive root -5).
Cf. bases 2..10: A014664, A062117, A082654, A211241, A211242, A211243, A211244, A211245, A002371.
Cf. bases -2..-10: A337878 (if first term 1), A380482, A380531, this sequence, A380533, A380540, A380541, A380542, A385222.

A380532[n_] := If[n == 3, 0, MultiplicativeOrder[-5, Prime[n]]];
Array[A380532, 100] (* Paolo Xausa, Jun 29 2025 *)

a(n,{k=-5}) = my(p = prime(n)); if(k%p==0, 0, znorder(Mod(k,p)))

cp's OEIS Frontend

A167801 Numbers with primitive root -5.

Views

Author

Keywords

Links

Crossrefs

Programs

Mathematica