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 A053379 #5 Jun 13 2020 15:16:32 %S A053379 8,88,888,7888,77888,877888,7877888,87877888,787877888,8787877888, %T A053379 88787877888,888787877888,8888787877888,88888787877888, %U A053379 788888787877888,8788888787877888,88788888787877888,888788888787877888 %N A053379 a(n) contains n digits (either '7' or '8') and is divisible by 2^n. %H A053379 Ray Chandler, <a href="/A053379/b053379.txt">Table of n, a(n) for n = 1..1000</a> %F A053379 a(n)=a(n-1)+10^(n-1)*(8-[a(n-1)/2^(n-1) mod 2]) i.e. a(n) ends with a(n-1); if (n-1)-th term is divisible by 2^n then n-th term begins with an 8, if not then n-th term begins with a 7. %Y A053379 Cf. A023414, A050621, A050622, A035014. %K A053379 base,nonn %O A053379 1,1 %A A053379 _Henry Bottomley_, Mar 06 2000