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 A031141 #32 Feb 16 2025 08:32:35 %S A031141 2,5,8,11,12,13,14,23,36,38,54,57,59,93,115,119,120,121,136,138,164, %T A031141 174,176,191,196,212,217,227,233,249 %N A031141 Position of rightmost digit 0 in 2^A031140(n). %C A031141 "Positions" are counted 0,1,2,3,... starting with the least significant digit. %H A031141 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/Zero.html">Zero.</a> %t A031141 best = 0; %t A031141 x = Select[Range[10000], %t A031141 If[(t = First@ %t A031141 First@StringPosition[StringReverse@ToString@(2^#), "0"]) > %t A031141 best, best = t; True] &] ; %t A031141 First /@ First /@ %t A031141 StringPosition[StringReverse[ToString /@ (2^x)], %t A031141 "0"] - 1 (* _Robert Price_, Oct 11 2019 *) %o A031141 (PARI) m=0;for(k=0,oo,d=digits(2^k);for(j=0,#d-1,d[#d-j]||(j>m&&print1(m=j,",")||break))) \\ _M. F. Hasler_, Jun 21 2018 %Y A031141 Cf. A031140, A031142, A031143. %K A031141 nonn,base,more %O A031141 1,1 %A A031141 _Matthew Cook_, _Dan Hoey_, _Eric W. Weisstein_, _David W. Wilson_ %E A031141 More terms from _Dan Hoey_