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 A343915 #37 Jun 07 2021 00:20:47
%S A343915 1,2,4,5,7,8,14,28,42,57,71,85,142,285,428,571,714,857,1428,2857,4285,
%T A343915 5714,7142,8571,14285,28571,42857,57142,71428,85714,142857,285714,
%U A343915 428571,571428,714285,857142,1428571,2857142,4285714,5714285,7142857,8571428,14285714
%N A343915 a(n) = floor(((n mod 6)+1) * 10^floor((n/6)+1) / 7).
%C A343915 Every digit string (after the decimal point) in the decimal expansion of 1/7 = 0.142857142857142857... forms a term of this sequence.
%H A343915 Konstantin Kutsenko, <a href="https://github.com/constcut/cyclicprime-cli">Python module used to generate sequences from different numbers</a>
%F A343915 a(n) = floor(((n mod 6)+1) * 10^floor((n/6)+1) / 7).
%e A343915 Every 6th term of the sequence starts with the same digits:
%e A343915 1, 2, 4, 5, 7, 8,
%e A343915 14, 28, 42, 57, 71, 85,
%e A343915 142, 285, 428, 571, 714, 857,
%e A343915 1428, 2857, 4285, 5714, 7142, 8571,
%e A343915 14285, 28571, 42857, 57142, 71428, 85714,
%e A343915 142857, 285714, 428571, 571428, 714285, 857142,
%e A343915 1428571, 2857142, 4285714, 5714285, 7142857, 8571428,
%e A343915 14285714, 28571428, 42857142, 57142857, 71428571, 85714285,
%e A343915 ...
%o A343915 (PARI) a(n) = {((n % 6)+1)*10^(n\6+1)\7} \\ _Andrew Howroyd_, May 05 2021
%Y A343915 Cf. A020806, A241217, A343833.
%K A343915 nonn,base
%O A343915 0,2
%A A343915 _Konstantin Kutsenko_, May 04 2021