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 A054710 #20 Aug 25 2024 10:00:26
%S A054710 1,2,1,3,2,2,6,4,1,2,2,3,6,7,2,5,16,2,18,3,6,3,22,4,3,7,3,8,28,2,15,6,
%T A054710 2,17,7,3,3,19,6,4,5,7,21,4,2,23,46,5,42,3,16,8,13,4,3,9,18,29,58,3,
%U A054710 60,16,6,7,7,3,33,18,22,7,35,4,8,4,3,20,6,7,13,5,9,6,41,8,17,22,28,5,44,2
%N A054710 Number of powers of 10 mod n.
%H A054710 Amiram Eldar, <a href="/A054710/b054710.txt">Table of n, a(n) for n = 1..10000</a> (terms 1..1000 from T. D. Noe)
%F A054710 a(n) = A007732(n) + A051628(n). - _Amiram Eldar_, Aug 25 2024
%t A054710 Table[Length[Union[PowerMod[10, Range[0,n], n]]], {n,100}] (* _T. D. Noe_, Aug 30 2006 *)
%t A054710 a[n_] := Module[{e = IntegerExponent[n, {2, 5}]}, Max[e] + MultiplicativeOrder[10, n/Times @@ ({2, 5}^e)]]; Array[a, 100] (* _Amiram Eldar_, Aug 25 2024 *)
%Y A054710 Cf. A007732, A051628, A121341.
%Y A054710 Cf. A054703 (base 2), A054704 (3), A054705 (4), A054706 (5), A054707 (6), A054708 (7), A054709 (8), A054717 (9), A351524 (11), A054712 (12), A054713 (13), A054714 (14), A054715 (15), A054716 (16).
%K A054710 easy,nonn
%O A054710 1,2
%A A054710 _Henry Bottomley_, Apr 20 2000