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 A102663 #18 Jul 19 2021 04:13:47 %S A102663 1,2,4,80,81,100,800,1000,1001,1002,2000,8001,10001,10002,10003,30001, %T A102663 100001,100002,100003,300001,1000000,1000001,2000001,10000001, %U A102663 10000002,40000000,200000001,1000000001,1000000002,2000000000,8000000001,10000000001,10000000002 %N A102663 Lexicographically earliest increasing sequence whose k-th digit is the absolute difference between the two digits touching the k-th comma. %e A102663 The first comma is touched by digits 1 and 2 which subtracted absolutely give 1, the first digit of the sequence. %e A102663 The 2nd comma is touched by digits 2 and 4 which subtracted absolutely give 2, the 2nd digit of the sequence. %e A102663 The 3rd comma is touched by digits 4 and 8 which subtracted absolutely give 4, the 3rd digit of the sequence. %Y A102663 Cf. A334336. %K A102663 base,easy,nonn %O A102663 1,2 %A A102663 _Eric Angelini_ and _Alexandre Wajnberg_, Feb 03 2005 %E A102663 a(15) corrected and a(16) onwards from _Mohammed Yaseen_, Jul 10 2021