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 A053316 #8 Oct 27 2019 17:30:16 %S A053316 2,32,232,3232,23232,223232,2223232,32223232,232223232,3232223232, %T A053316 23232223232,323232223232,3323232223232,23323232223232, %U A053316 323323232223232,3323323232223232,33323323232223232,333323323232223232 %N A053316 a(n) contains n digits (either '2' or '3') and is divisible by 2^n. %H A053316 Robert Israel, <a href="/A053316/b053316.txt">Table of n, a(n) for n = 1..999</a> %F A053316 a(n) = a(n-1) + 10^(n-1)*(2 + (a(n-1)/2^(n-1) mod 2)), i.e., a(n) ends with a(n-1); if a(n-1) is divisible by 2^n then a(n) begins with a 2, if not then a(n) begins with a 3. %p A053316 A[1]:= 2: %p A053316 for n from 2 to 100 do %p A053316 if A[n-1] mod 2^n = 0 then A[n]:= A[n-1]+2*10^(n-1) %p A053316 else A[n]:= A[n-1]+3*10^(n-1) %p A053316 fi %p A053316 od: %p A053316 seq(A[i],i=1..100); # _Robert Israel_, Oct 27 2019 %Y A053316 Cf. A023397, A050621, A050622, A035014. %K A053316 base,nonn %O A053316 1,1 %A A053316 _Henry Bottomley_, Mar 06 2000 %E A053316 Formula corrected by _Robert Israel_, Oct 27 2019