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 A325600 #8 Dec 15 2024 16:28:55
%S A325600 1,2,3,5,7,9,10,11,13,14,16,17,18,20,21,23,24,25,27,28,30,32,34,35,36,
%T A325600 38,39,41,43,44,45,47,48,50,52,54,55,56,58,59,61,63,64,65,67,68,70,72,
%U A325600 74,75,76,78,79,81,83,84,85,87,88,90,91,92,94,95,97,98
%N A325600 Positions of 1 in A325599.
%C A325600 All the terms of A325599 are in {1,2}, so that A325600 and A325601 are a complementary pair.
%H A325600 Clark Kimberling, <a href="/A325600/b325600.txt">Table of n, a(n) for n = 1..10000</a>
%t A325600 mex[list_, start_] := (NestWhile[# + 1 &, start, MemberQ[list, #] &]); a = {1}; Do[AppendTo[a, mex[Rest[2 a] + Most[a], Last[a] + 1]], {60}]; a (* A325597 *)
%t A325600 c = Complement[Range[Last[a]], a] (* A325598 *)
%t A325600 da = Differences[a] (* A325599 *)
%t A325600 Flatten[Position[da, 1]] (* A325600 *)
%t A325600 Flatten[Position[da, 2]] (* A325601 *)
%t A325600 (* _Peter J. C. Moses_, May 07 2019 *)
%Y A325600 Cf. A325597, A325599, A325601.
%K A325600 nonn,easy
%O A325600 1,2
%A A325600 _Clark Kimberling_, May 11 2019