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A054708
Number of powers of 7 modulo n.
15
1, 1, 1, 2, 4, 1, 2, 2, 3, 4, 10, 2, 12, 2, 4, 2, 16, 3, 3, 4, 2, 10, 22, 2, 4, 12, 9, 3, 7, 4, 15, 4, 10, 16, 5, 6, 9, 3, 12, 4, 40, 2, 6, 10, 12, 22, 23, 2, 3, 4, 16, 12, 26, 9, 20, 3, 3, 7, 29, 4, 60, 15, 4, 8, 12, 10, 66, 16, 22, 5, 70, 6, 24, 9, 4, 6, 11, 12, 78, 4, 27, 40, 41, 3, 16, 6
OFFSET
1,4
LINKS
Amiram Eldar, Table of n, a(n) for n = 1..10000 (terms 1..1000 from David W. Wilson)
FORMULA
a(n) = A007738(n) + A214411(n). - Amiram Eldar, Aug 25 2024
MATHEMATICA
a[n_] := Module[{e = IntegerExponent[n, 7]}, e + MultiplicativeOrder[7, n/7^e]]; Array[a, 100] (* Amiram Eldar, Aug 25 2024 *)
CROSSREFS
Cf. A054703 (base 2), A054704 (3), A054705 (4), A054706 (5), A054707 (6), A054709 (8), A054717 (9), A054710 (10), A351524 (11), A054712 (12), A054713 (13), A054714 (14), A054715 (15), A054716 (16).
Sequence in context: A305717 A208645 A361381 * A112229 A375484 A087419
KEYWORD
easy,nonn
AUTHOR
Henry Bottomley, Apr 20 2000
STATUS
approved