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 A285681 #12 Mar 11 2025 02:54:44 %S A285681 1,3,4,6,8,9,11,13,15,16,18,20,21,23,25,27,28,30,32,34,35,37,39,40,42, %T A285681 44,46,47,49,51,52,54,56,58,59,61,63,65,66,68,70,71,73,75,77,78,80,82, %U A285681 84,85,87,89,90,92,94,96,97,99,101,102,104,106,108,109 %N A285681 Positions of 0 in A285680. %C A285681 A 3-way partition of the positive integers, by positions of 0, 1, 2 in A285680: %C A285681 A285681: positions of 0; slope t = (15+sqrt(5))/10; %C A285681 A285682: positions of 1; slope u = 4+sqrt(5); %C A285681 A285683: positions of 2; slope v = (1+3*sqrt(5))/2; %C A285681 where 1/t + 1/u + 1/v = 1. Conjecture: a(n) - a(n-1) is in {1,2} for n >= 2. %H A285681 Clark Kimberling, <a href="/A285681/b285681.txt">Table of n, a(n) for n = 1..10000</a> %t A285681 s = Nest[Flatten[# /. {0 -> {0, 1}, 1 -> {0}}] &, {0}, 13] ; (* A003849 *) %t A285681 w = StringJoin[Map[ToString, s]] %t A285681 w1 = StringReplace[w, {"1010" -> "2"}] %t A285681 st = ToCharacterCode[w1] - 48; (* A285680 *) %t A285681 Flatten[Position[st, 0]]; (* A285681 *) %t A285681 Flatten[Position[st, 1]]; (* A285682 *) %t A285681 Flatten[Position[st, 2]]; (* A285683 *) %Y A285681 Cf. A003849, A285680, A285682, A285683. %K A285681 nonn,easy %O A285681 1,2 %A A285681 _Clark Kimberling_, May 11 2017