A054715 Number of powers of 15 modulo n.

1, 1, 2, 2, 2, 2, 1, 2, 3, 2, 5, 3, 12, 1, 2, 2, 8, 3, 18, 3, 2, 5, 22, 3, 3, 12, 4, 2, 28, 2, 10, 2, 6, 8, 2, 4, 36, 18, 13, 3, 40, 2, 21, 10, 3, 22, 46, 3, 7, 3, 9, 12, 13, 4, 6, 2, 19, 28, 29, 3, 15, 10, 3, 4, 13, 6, 11, 8, 23, 2, 35, 4, 72, 36, 3, 18, 5, 13, 26, 3, 5, 40, 82, 3, 9, 21, 29

Offset: 1

Author

Henry Bottomley, Apr 20 2000

Keywords

• easy
• nonn

Links

• Amiram Eldar, Table of n, a(n) for n = 1..10000

Crossrefs

Cf. A054703 (base 2), A054704 (3), A054705 (4), A054706 (5), A054707 (6), A054708 (7), A054709 (8), A054717 (9), A054710 (10), A351524 (11), A054712 (12), A054713 (13), A054714 (14), A054716 (16).

Programs

Mathematica

a[n_] := Module[{e = IntegerExponent[n, {3, 5}]}, Max[e] + MultiplicativeOrder[15, n/Times @@ ({3, 5}^e)]]; Array[a, 100] (* Amiram Eldar, Aug 25 2024 *)