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 A061519 #10 Jan 23 2025 19:17:13
%S A061519 1,6,11,66,1111,6666,11111111,66666666,1111111111111111,
%T A061519 6666666666666666,11111111111111111111111111111111,
%U A061519 66666666666666666666666666666666
%N A061519 a(0) = 1; a(n) is obtained by incrementing each digit of a(n-1) by 5.
%C A061519 In A061511-A061522, A061746-A061750 when the incremented digit exceeds 9 it is written as a 2-digit string. So 9+1 becomes the 2-digit string 10, etc.
%C A061519 Number of digits of each term is the sequence A016116. [From _Dmitry Kamenetsky_, Jan 17 2009]
%H A061519 Harvey P. Dale, <a href="/A061519/b061519.txt">Table of n, a(n) for n = 0..13</a>
%F A061519 a(2n) = 6*[10^{2^(n)} - 1]/9 a(2n+1) = [10^(2^n) - 1]/9
%t A061519 With[{nn=5},Join[Table[FromDigits[PadRight[{},2^n,1]],{n,0,nn}],Table[FromDigits[PadRight[{},2^n,6]],{n,0,nn}]]]//Sort (* _Harvey P. Dale_, Jan 23 2025 *)
%K A061519 base,nonn
%O A061519 0,2
%A A061519 _Amarnath Murthy_, May 08 2001
%E A061519 More terms from Larry Reeves (larryr(AT)acm.org), May 11 2001