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 A325601 #8 Dec 15 2024 16:29:37
%S A325601 4,6,8,12,15,19,22,26,29,31,33,37,40,42,46,49,51,53,57,60,62,66,69,71,
%T A325601 73,77,80,82,86,89,93,96,100,103,105,107,111,114,116,120,123,127,130,
%U A325601 132,134,138,141,143,147,150,154,157,161,164,166,168,172,175,177
%N A325601 Positions of 2 in A325599.
%C A325601 All the terms of A325599 are in {1,2}, so that A325600 and A325601 are a complementary pair.
%H A325601 Clark Kimberling, <a href="/A325601/b325601.txt">Table of n, a(n) for n = 1..10000</a>
%t A325601 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 A325601 c = Complement[Range[Last[a]], a] (* A325598 *)
%t A325601 da = Differences[a] (* A325599 *)
%t A325601 Flatten[Position[da, 1]] (* A325600 *)
%t A325601 Flatten[Position[da, 2]] (* A325601 *)
%t A325601 (* _Peter J. C. Moses_, May 07 2019 *)
%Y A325601 Cf. A325597, A325599, A325600.
%K A325601 nonn,easy
%O A325601 1,1
%A A325601 _Clark Kimberling_, May 11 2019