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 A197226 #9 Oct 25 2019 15:31:04
%S A197226 1,2,16,3,5,13,8,13,41,4,53,8,81,43,113,7,256,5,79,173,32,179,32,233,
%T A197226 239,281,293,32,107,359,61,125,27,193,199,419,151,103,593,41,641,653,
%U A197226 659,32,719,373,761,271,409,313,953,331,1013,1019,137,619,223,31
%N A197226 The period of the decimal fraction 1/A197225(n).
%C A197226 These numbers are prime powers, members of A000961.
%H A197226 Ray Chandler, <a href="/A197226/b197226.txt">Table of n, a(n) for n = 1..1000</a>
%t A197226 myPerfectPowerQ[n_] := Length[FactorInteger[n]] == 1; t=Select[Prime[Range[500]], Mod[10,#] > 0 && myPerfectPowerQ[Length[RealDigits[1/#, 10][[1,1]]]] &]; Table[Length[RealDigits[1/n, 10][[1,1]]], {n, t}]
%K A197226 nonn,base
%O A197226 1,2
%A A197226 _T. D. Noe_, Oct 22 2011