A070678 Smallest m in range 1..phi(n) such that 7^m == 1 mod n, or 0 if no such number exists.

0, 1, 1, 2, 4, 1, 0, 2, 3, 4, 10, 2, 12, 0, 4, 2, 16, 3, 3, 4, 0, 10, 22, 2, 4, 12, 9, 0, 7, 4, 15, 4, 10, 16, 0, 6, 9, 3, 12, 4, 40, 0, 6, 10, 12, 22, 23, 2, 0, 4, 16, 12, 26, 9, 20, 0, 3, 7, 29, 4, 60, 15, 0, 8, 12, 10, 66, 16, 22, 0, 70, 6, 24, 9, 4, 6, 0, 12

Offset: 1

Author

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

Keywords

• nonn

Links

• Harvey P. Dale, Table of n, a(n) for n = 1..1000

Crossrefs

Cf. A070667-A070675, A002326, A070676, A053447, A070677, A070681, A053451, A070679, A070682, A070680, A070683.

Programs

Magma

[0] cat [Modorder(7, n): n in [2..100]]; // Vincenzo Librandi, Apr 01 2014

Mathematica

Table[SelectFirst[Range[EulerPhi[n]],PowerMod[7,#,n]==1&],{n,80}]/.(Missing["NotFound"]->0) (* Requires Mathematica version 10 or later *) (* Harvey P. Dale, Jan 25 2019 *)