A070677 Smallest m in range 1..phi(n) such that 5^m == 1 mod n, or 0 if no such number exists.

0, 1, 2, 1, 0, 2, 6, 2, 6, 0, 5, 2, 4, 6, 0, 4, 16, 6, 9, 0, 6, 5, 22, 2, 0, 4, 18, 6, 14, 0, 3, 8, 10, 16, 0, 6, 36, 9, 4, 0, 20, 6, 42, 5, 0, 22, 46, 4, 42, 0, 16, 4, 52, 18, 0, 6, 18, 14, 29, 0, 30, 3, 6, 16, 0, 10, 22, 16, 22, 0, 5, 6, 72, 36, 0, 9, 30, 4, 39, 0

Offset: 1

Author

N. J. A. Sloane and Amarnath Murthy, May 08 2002

Keywords

• nonn

Crossrefs

Cf. A070667-A070675, A002326, A070676, A053447, A070681, A070678, A053451, A070679, A070682, A070680, A070683.

Programs

Magma

[0] cat [Modorder(5, n): n in [2..100]]; // Vincenzo Librandi, Apr 01 2014

Mathematica

Table[SelectFirst[Range[EulerPhi[n]], PowerMod[5, #, n] == 1 &, 0],{n, 80}] (* Paul F. Marrero Romero, Oct 04 2024 *)

Python

from sympy import n_order
def A070677(n): return n_order(5,n) if n%5 and n>1 else 0 # Chai Wah Wu, Feb 23 2023