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%I #9 Aug 25 2024 10:00:42
%S 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,
%T 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,
%U 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
%N Number of powers of 15 modulo n.
%H Amiram Eldar, <a href="/A054715/b054715.txt">Table of n, a(n) for n = 1..10000</a>
%t 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 *)
%Y 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).
%K easy,nonn
%O 1,3
%A _Henry Bottomley_, Apr 20 2000