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 A104321 #13 Aug 17 2024 22:51:11
%S A104321 0,5,8,18,13,26,27,23,42,25,37,58,47,46,61,67,54,71,77,73,88,99,141,
%T A104321 100,115,114,119,117,113,112,109,135,110,127,133,136,164,162,177,186,
%U A104321 193,195,163,189,201,196,191,199,206,188,208,200,221,266,235,234,238,280
%N A104321 Smallest number m such that A104320(m)=n.
%C A104321 A104320(a(n))=n and A104320(m)<>n for m<a(n).
%C A104321 If it exists, a(115) > 10^5. - _Michel Marcus_, Oct 19 2016
%H A104321 Michel Marcus, <a href="/A104321/b104321.txt">Table of n, a(n) for n = 0..114</a>
%o A104321 (PARI) a(n) = {my(k = 0); while (#select(x->(x==0), digits(2^k, 3)) != n, k++); k;} \\ _Michel Marcus_, Oct 19 2016
%Y A104321 Cf. A036462, A060035, A104320, A375472.
%K A104321 nonn
%O A104321 0,2
%A A104321 _Reinhard Zumkeller_, Mar 01 2005