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 A021025 #18 Sep 29 2023 13:53:44
%S A021025 0,4,7,6,1,9,0,4,7,6,1,9,0,4,7,6,1,9,0,4,7,6,1,9,0,4,7,6,1,9,0,4,7,6,
%T A021025 1,9,0,4,7,6,1,9,0,4,7,6,1,9,0,4,7,6,1,9,0,4,7,6,1,9,0,4,7,6,1,9,0,4,
%U A021025 7,6,1,9,0,4,7,6,1,9,0,4,7,6,1,9,0,4,7,6,1,9,0,4,7,6,1,9,0,4,7
%N A021025 Decimal expansion of 1/21.
%H A021025 <a href="/index/Rec#order_06">Index entries for linear recurrences with constant coefficients</a>, signature (0, 0, 0, 0, 0, 1).
%e A021025 0.047619047...
%t A021025 Join[{0}, RealDigits[10/21, 10, 105][[1]]] (* _Alonso del Arte_, Mar 07 2019 *)
%o A021025 (PARI) 1/21. \\ _Charles R Greathouse IV_, Mar 08 2019
%Y A021025 Cf. A010701 (1/3), A020806 (1/7).
%K A021025 nonn,cons,easy
%O A021025 0,2
%A A021025 _N. J. A. Sloane_