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 A129185 #14 Feb 18 2022 22:28:24
%S A129185 0,1,0,0,1,0,0,0,1,0,0,0,0,1,0,0,0,0,0,1,0,0,0,0,0,0,1,0,0,0,0,0,0,0,
%T A129185 1,0,0,0,0,0,0,0,0,1,0,0,0,0,0,0,0,0,0,1,0,0,0,0,0,0,0,0,0,0,1,0,0,0,
%U A129185 0,0,0,0,0,0,0,0,1,0,0,0,0,0,0,0,0,0,0,0,0,1,0,0,0,0,0,0,0
%N A129185 Shift operator, left.
%C A129185 Let A129185 = M, then M*V (V a vector), shifts V to the left. Example M*V, V = [1, 2, 3, ...] = [2, 3, 4, ...]. A129184 = right shift operator.
%H A129185 Franck Ramaharo, <a href="https://arxiv.org/abs/2002.06672">A bracket polynomial for 2-tangle shadows</a>, arXiv:2002.06672 [math.CO], 2020.
%F A129185 As an infinite matrix, all 1's in the superdiagonal and the rest zeros.
%e A129185 First few rows of the matrix:
%e A129185 0, 1;
%e A129185 0, 0, 1;
%e A129185 0, 0, 0, 1;
%e A129185 0, 0, 0, 0, 1;
%e A129185 ...
%t A129185 Table[PadLeft[{1},n,0],{n,20}]//Flatten//Rest (* _Harvey P. Dale_, Jul 11 2020 *)
%Y A129185 Cf. A129184, A129186.
%K A129185 nonn,tabf,easy,less
%O A129185 1,1
%A A129185 _Gary W. Adamson_, Apr 01 2007