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 A338265 #12 Feb 07 2021 17:04:45 %S A338265 1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,21,20,11,31,23,22,24, %T A338265 25,26,27,28,29,32,30,12,41,34,33,35,36,37,38,39,43,40,13,51,45,42,44, %U A338265 46,47,48,49,54,50,14,61,56,52,53,55,57,58,59,65,60,15,71,67,62,63,64,66,68,69,76,70,16,81,78,72 %N A338265 If a(n) has at least one common digit with a(n-1), underline a(n). The non-underlined terms reproduce the sequence itself. %C A338265 This is a kind of fractal sequence as it contains an infinite number of copies of itself. The underlined terms of the sequence are the lexicographically earliest permutation of the natural numbers > 10. %e A338265 If we erase the parenthesized terms, we get the sequence itself: 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, (11, 12, 13, 14, 15, 16, 17, 18, 19, 21, 20), 11, (31, 23, 22, 24, 25, 26, 27, 28, 29, 32, 30), 12, (41, 34, 33, 35, 36, 37, 38, 39, 43, 40), 13, (51, 45, 42, 44, 46, 47, 48, 49, 54, 50), 14, (61, 56, 52, 53, 55, 57, 58, 59, 65, 60), 15, (71, 67, 62, 63, 64, 66, 68, 69, 76, 70), 16, (81, 78, 72, ...) etc. %Y A338265 Cf. A274329. %K A338265 base,nonn %O A338265 1,2 %A A338265 _Eric Angelini_, Oct 19 2020