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 A284882 #9 Jun 25 2017 10:46:29
%S A284882 2,5,8,11,15,18,20,23,26,29,33,36,38,41,45,48,50,53,56,59,62,65,69,72,
%T A284882 74,77,80,83,87,90,92,95,99,102,104,107,110,113,116,119,123,126,128,
%U A284882 131,135,138,140,143,146,149,152,155,159,162,164,167,170,173,177
%N A284882 Positions of -1 in A284881.
%C A284882 This sequence and A284883 and A284884 form a partition of the positive integers. For n>=1, we have 3n-a(n) in {0,1}, 3*n+1-A284883(n) in {0,1,2,3}, and 3*n-1-A284884(n) in {0,1,2}.
%C A284882 A284881 = (1,-1,1,0,-1,0,1,-1,1,0,-1,0,1,0,...); thus
%C A284882 A284882 = (2,5,8,11,15,18,...)
%C A284882 A284883 = (4,6,10,12,14,16,...)
%C A284882 A284884 = (1,3,7,9,13,17,...).
%H A284882 Clark Kimberling, <a href="/A284882/b284882.txt">Table of n, a(n) for n = 1..10000</a>
%t A284882 s = Nest[Flatten[# /. {0 -> {0, 1}, 1 -> {0, 1, 1, 0}}] &, {0}, 6] (* A284878 *)
%t A284882 d = Differences[s] (* A284881 *)
%t A284882 Flatten[Position[d, -1]] (* A284882 *)
%t A284882 d2 = Flatten[Position[d, 0]] (* A284883 *)
%t A284882 Flatten[Position[d, 1]] (* A284884 *)
%t A284882 d2/2 (* A284885 *)
%Y A284882 Cf. A284793, A284881, A284883, A284884.
%K A284882 nonn,easy
%O A284882 1,1
%A A284882 _Clark Kimberling_, Apr 16 2017