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 A214651 #15 Feb 16 2025 08:33:18
%S A214651 1,2,1,2,1,3,2,1,3,2,1,3,2,1,4,3,2,1,4,3,2,1,4,3,2,1,4,3,2,1,5,4,3,2,
%T A214651 1,5,4,3,2,1,5,4,3,2,1,5,4,3,2,1,5,4,3,2,1,6,5,4,3,2,1,6,5,4,3,2,1,6,
%U A214651 5,4,3,2,1,6,5,4,3,2,1,6,5,4,3,2,1,6,5
%N A214651 Count down from n to 1, n times.
%C A214651 This sequence contains every positive integer infinitely often.
%C A214651 This is a fractal sequence. Striking out the first instance of every term produces 1, 2, 1, 2, 1, 3, 2, 1, 3, 2, 1, 3, ..., which is the same as the original sequence, as far as it goes.
%H A214651 Arkadiusz Wesolowski, <a href="/A214651/b214651.txt">Rows n = 1..14 of triangle, flattened</a>
%H A214651 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/PositiveInteger.html">Positive Integer</a>
%H A214651 Wikipedia, <a href="http://en.wikipedia.org/wiki/Fractal_sequence">Fractal sequence</a>
%e A214651 1;
%e A214651 2, 1, 2, 1;
%e A214651 3, 2, 1, 3, 2, 1, 3, 2, 1;
%e A214651 ...
%t A214651 f[n_] := Table[Range[n, 1, -1], {n}]; Flatten@Array[f, 6] (* Wesolowski *)
%t A214651 Flatten[Table[Table[Range[n, 1, -1], {n}], {n, 6}]] (* _Alonso del Arte_, Jul 24 2012 *)
%Y A214651 Cf. A056520 (locations of new values), A060432 (locations of 1's).
%Y A214651 Cf. A000290 (row lengths), A002411 (row sums), A036740 (row products).
%K A214651 easy,nonn,tabf
%O A214651 1,2
%A A214651 _Arkadiusz Wesolowski_, Jul 24 2012