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 A026184 #26 Sep 25 2024 13:54:44
%S A026184 1,3,5,2,7,9,11,4,13,15,17,6,19,21,23,8,25,27,29,10,31,33,35,12,37,39,
%T A026184 41,14,43,45,47,16,49,51,53,18,55,57,59,20,61,63,65,22,67,69,71,24,73,
%U A026184 75,77,26,79,81,83,28,85,87,89,30,91,93,95
%N A026184 a(n) = (1/3)*s(n), where s(n) is the n-th multiple of 3 in A026136.
%H A026184 Michael De Vlieger, <a href="/A026184/b026184.txt">Table of n, a(n) for n = 1..10000</a>
%H A026184 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.
%H A026184 <a href="/index/Rec#order_08">Index entries for linear recurrences with constant coefficients</a>, signature (0,0,0,2,0,0,0,-1).
%F A026184 a(4*n) = 2*n, a(4*n+1) = 6*n+1, a(4*n+2) = 6*n+3, a(4*n+3) = 6*n+5 . - _Philippe Deléham_, Nov 02 2023
%t A026184 Block[{a, r, s, nn = 141}, a[1] = 1; Do[If[! IntegerQ[a[#1]], Set[a[#1], i], Set[a[#2], i]] & @@ {i - #, i + #} &@ Floor[i/2], {i, 2 nn}]; Select[TakeWhile[Array[a[#] &, nn], IntegerQ], Mod[#, 3] == 0 &]/3] (* _Michael De Vlieger_, Aug 27 2021 *)
%t A026184 LinearRecurrence[{0,0,0,2,0,0,0,-1},{1,3,5,2,7,9,11,4},70] (* _Harvey P. Dale_, Sep 25 2024 *)
%Y A026184 Cf. A026136, A026185.
%K A026184 nonn,easy
%O A026184 1,2
%A A026184 _Clark Kimberling_
%E A026184 Edited by _N. J. A. Sloane_, Jan 31 2020