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 A326663 #7 Dec 06 2019 04:14:36
%S A326663 5,12,20,26,33,41,47,54,61,68,75,83,89,96,104,110,117,124,131,138,146,
%T A326663 152,159,167,173,180,188,194,201,209,215,222,230,236,243,250,257,264,
%U A326663 272,278,285,293,299,306,313,320,327,335,341,348,356,362,369,377,383
%N A326663 Column 3 of the array at A309157; see Comments.
%C A326663 This is the sequence (c(n)) defined by the complementary equation c(n) = a(n) + b(2n), with initial value a(1) = 1. See A309157. Conjecture: 7n-c(n) is in {1,2} for all n.
%H A326663 Clark Kimberling, <a href="/A326663/b326663.txt">Table of n, a(n) for n = 1..10000</a>
%t A326663 mex[list_, start_] := (NestWhile[# + 1 &, start, MemberQ[list, #] &]);
%t A326663 a = b = c = {}; h = 1; k = 2;
%t A326663 Do[Do[AppendTo[a,
%t A326663 mex[Flatten[{a, b, c}], Max[Last[a /. {} -> {0}], 1]]];
%t A326663 AppendTo[b, mex[Flatten[{a, b, c}], Max[Last[b /. {} -> {0}], 1]]], {k}];
%t A326663 AppendTo[c, a[[h Length[a]/k]] + Last[b]], {150}]; c
%t A326663 (* _Peter J. C. Moses_, Jul 04 2019 *)
%Y A326663 Cf. A309157.
%K A326663 nonn,tabl,easy
%O A326663 1,1
%A A326663 _Clark Kimberling_, Jul 16 2019