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 A284884 #12 Nov 23 2019 13:38:48
%S A284884 1,3,7,9,13,17,19,21,25,27,31,35,37,39,43,47,49,51,55,57,61,63,67,71,
%T A284884 73,75,79,81,85,89,91,93,97,101,103,105,109,111,115,117,121,125,127,
%U A284884 129,133,137,139,141,145,147,151,153,157,161,163,165,169,171,175
%N A284884 Positions of 1's in A284881.
%C A284884 This sequence and A284882 and A284883 form a partition of the positive integers. Conjecture: for n>=1, we have a(n)-3n-3 in {0,1,2}, 3*n+1-A284883(n) in {0,1,2,3}, and 3*n-1-A284884(n) in {0,1,2}.
%C A284884 A284881 = (1,-1,1,0,-1,0,1,-1,1,0,-1,0,1,0,...); thus
%C A284884 A284882 = (2,5,8,11,15,18,...)
%C A284884 A284883 = (4,6,10,12,14,16,...)
%C A284884 A284884 = (1,3,7,9,13,17,...).
%H A284884 Clark Kimberling, <a href="/A284884/b284884.txt">Table of n, a(n) for n = 1..10000</a>
%t A284884 s = Nest[Flatten[# /. {0 -> {0, 1}, 1 -> {0, 1, 1, 0}}] &, {0}, 6] (* A284878 *)
%t A284884 d = Differences[s] (* A284881 *)
%t A284884 Flatten[Position[d, -1]] (* A284882 *)
%t A284884 d2 = Flatten[Position[d, 0]] (* A284883 *)
%t A284884 Flatten[Position[d, 1]] (* A284884 *)
%t A284884 d2/2 (* A284885 *)
%Y A284884 Cf. A284793, A284881, A284882, A284883.
%K A284884 nonn,easy
%O A284884 1,2
%A A284884 _Clark Kimberling_, Apr 16 2017