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 A343215 #17 Apr 16 2021 00:17:58 %S A343215 1,1,1,1,1,1,1,1,1,1,9,2,8,3,7,4,6,5,5,6,4,7,3,8,2,9,1,1,9,1,89,2,18, %T A343215 2,78,3,27,3,67,4,36,4,56,5,45,5,45,6,54,6,34,7,63,7,23,8,72,8,12,9, %U A343215 81,9,1,1,9,1,89,1,9,1,889,2,18,2,178,2,18,2,778 %N A343215 Differences between consecutive numbers with unique nonzero digit in decimal representation. %F A343215 a(n) = A125289(n+1) - A125289(n). %Y A343215 First differences of A125289. %K A343215 nonn,base %O A343215 1,11 %A A343215 _Guillermo Miñones Collantes_, Apr 08 2021