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 A189637 #18 Jun 20 2022 13:57:54 %S A189637 3,6,8,9,12,15,17,18,21,23,24,26,27,30,33,35,36,39,42,44,45,48,50,51, %T A189637 53,54,57,60,62,63,66,68,69,71,72,75,77,78,80,81,84,87,89,90,93,96,98, %U A189637 99,102,104,105,107,108,111,114,116,117,120,123,125,126,129,131,132,134,135,138,141,143,144,147,149,150,152,153,156,158,159,161,162,165,168,170,171,174 %N A189637 Positions of 1 in A116178; complement of A189636. %C A189637 See A116178. %H A189637 Michael De Vlieger, <a href="/A189637/b189637.txt">Table of n, a(n) for n = 1..10000</a> %H A189637 F. M. Dekking, <a href="https://arxiv.org/abs/2001.08915">Permutations of N generated by left-right filling algorithms</a>, arXiv:2001.08915 [math.CO], 2020. %F A189637 A340407(a(n)) = A254046(a(n)). Discovered with help from sequencedb.net. - _Thomas Scheuerle_, Jun 20 2022 %t A189637 t = Nest[Flatten[# /. {0->{0,0,1}, 1->{0,1,1}}] &, {0}, 5] (* A116178 *) %t A189637 f[n_] := t[[n]] %t A189637 Flatten[Position[t, 0]] (* A189636 *) %t A189637 Flatten[Position[t, 1]] (* A189637 *) %t A189637 s[n_] := Sum[f[i], {i, 1, n}]; s[0] = 0; %t A189637 Table[s[n], {n, 1, 120}] (* A189638 *) %Y A189637 Cf. A116178, A189636, A189638, A254046, A340407. %K A189637 nonn %O A189637 1,1 %A A189637 _Clark Kimberling_, Apr 24 2011