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 A117970 #15 Feb 16 2025 08:33:00
%S A117970 0,0,0,0,0,3,2,2,4,4,5,4,2,2,4,0,3,4,2,2,3,3,8,3,2,2,5,5,6,5,2,2,11,4,
%T A117970 3,5,2,2,3,3,11,3,2,2,5,8,4,5,2,2,13,5,3,5,2,2,3,3,4,3,2,2,4,4,7,4,2,
%U A117970 2,4,6,3,4,2,2,3,3,7,3,2,2,6,6,7,6,2,2,10,4,3,7,2,2,3,3,5,3,2,2,11,5,4,17
%N A117970 Position of first 0 counting from the least significant digit in the ternary expansion of 2^n.
%H A117970 Rémy Sigrist, <a href="/A117970/b117970.txt">Table of n, a(n) for n = 0..10000</a>
%H A117970 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/Ternary.html">Ternary</a>
%o A117970 (PARI) a(n) = { my (p=2^n); for (k=1, oo, if (p==0, return (0), p%3==0, return (k), p\=3)) } \\ _Rémy Sigrist_, Dec 20 2019
%Y A117970 Cf. A004642, A102483, A104320, A117971.
%K A117970 nonn,base
%O A117970 0,6
%A A117970 _Eric W. Weisstein_, Apr 06 2006
%E A117970 Edited by _Charles R Greathouse IV_, Aug 05 2010
%E A117970 a(0) = 0 prepended by _Rémy Sigrist_, Dec 20 2019