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 A277733 #12 Mar 20 2023 06:24:40
%S A277733 2,4,7,9,13,15,18,20,24,26,28,31,33,37,39,42,44,48,50,52,55,57,60,62,
%T A277733 66,68,71,73,77,79,81,84,86,90,92,95,97,101,103,105,108,110,113,115,
%U A277733 119,121,124,126,130,132,135,137,141,143,145,148,150,154,156,159,161,165,167,169,172,174,177,179
%N A277733 Positions of 1's in A277731.
%C A277733 {A277732, A277733, A277734} forms a three-way partition of the positive integers, similar to {A003144, A003145, A003146}.
%H A277733 N. J. A. Sloane, <a href="/A277733/b277733.txt">Table of n, a(n) for n = 1..20000</a>
%p A277733 See A277732.
%t A277733 m = 1000; (* number of terms of A277731 *)
%t A277733 S[1] = {0};
%t A277733 S[n_] := S[n] = SubstitutionSystem[{0 -> {0, 1}, 1 -> {0, 1, 2}, 2 -> {0}}, S[n - 1]];
%t A277733 For[n = 2, True, n++, If[PadRight[S[n], m] == PadRight[S[n - 1], m], Print["n = ", n]; Break[]]];
%t A277733 A277731 = Take[S[n], m];
%t A277733 Position[A277731, 1] // Flatten (* _Jean-François Alcover_, Mar 20 2023 *)
%Y A277733 Cf. A052980, A277731, A277732, A277734.
%Y A277733 Cf. also A003144, A003145, A003146.
%K A277733 nonn
%O A277733 1,1
%A A277733 _N. J. A. Sloane_, Nov 07 2016