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 A375232 #7 Aug 06 2024 21:43:44 %S A375232 0,10,20,100,30,102,40,101,203,105,60,1024,300,107,200,150,304,1026, %T A375232 80,109,230,10457 %N A375232 Two terms that contain the digit "d" are always separated by "d" terms that do not contain the digit "d". This is the lexicographically earliest sequence of distinct nonnegative integers with this property. %C A375232 The sequence is finite, there is no 23rd term. %H A375232 Eric Angelini, <a href="https://cinquantesignes.blogspot.com/2024/08/digits-and-gaps.html">Digits and gaps</a>, personal blog of the author. %e A375232 As we start the sequence with a(1) = 0, the digit 0 must be present in every term of the sequence. %e A375232 We extend it now with a(2) = 10 as 10 is the smallest integer not present that contains the digit 0. %e A375232 The next term will be a(3) = 20 as 20 is the smallest integer not present that contains the digit 0. %e A375232 The next term will be a(4) = 100 as 100 is the smallest integer not present that contains both the digits 0 and 1. %e A375232 The next term will be a(5) = 30 as 30 is the smallest integer not present that contains the digit 0. %e A375232 The next term will be a(6) = 102 as 102 is the smallest integer not present that contains the digits 0, 1 and 2. %e A375232 The next term will be a(7) = 40 as 40 is the smallest integer not present that contains the digit 0. %e A375232 The next term will be a(8) = 101 as 101 is the smallest integer not present that contains both the digits 0 and 1. %e A375232 Etc. %Y A375232 Cf. A284516. %K A375232 nonn,base,fini,full %O A375232 1,2 %A A375232 _Eric Angelini_ and _Jean-Marc Falcoz_, Aug 06 2024 %E A375232 a(14) and successive terms computed by Michael S. Branicky.