This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A054713 #9 Aug 25 2024 10:00:34
%S A054713 1,1,1,1,4,1,2,2,3,4,10,1,2,2,4,4,4,3,18,4,2,10,11,2,20,2,9,2,14,4,30,
%T A054713 8,10,4,4,3,36,18,2,4,40,2,21,10,12,11,46,4,14,20,4,2,13,9,20,2,18,14,
%U A054713 58,4,3,30,6,16,5,10,66,4,11,4,70,6,72,36,20,18,10,2,39,4,27,40,82,2,4
%N A054713 Number of powers of 13 modulo n.
%H A054713 Amiram Eldar, <a href="/A054713/b054713.txt">Table of n, a(n) for n = 1..10000</a>
%t A054713 a[n_] := Module[{e = IntegerExponent[n, 13]}, e + MultiplicativeOrder[13, n/13^e]]; Array[a, 100] (* _Amiram Eldar_, Aug 25 2024 *)
%Y A054713 Cf. A054703 (base 2), A054704 (3), A054705 (4), A054706 (5), A054707 (6), A054708 (7), A054709 (8), A054717 (9), A054710 (10), A351524 (11), A054712 (12), A054714 (14), A054715 (15), A054716 (16).
%K A054713 easy,nonn
%O A054713 1,5
%A A054713 _Henry Bottomley_, Apr 20 2000