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 A096549 #30 Apr 05 2025 22:43:24 %S A096549 1,6,10,11,19,43,50,50,71,71,523,590,590,12106,12106,12106,12106, %T A096549 56590,505206,1570511,1570511,4033966,4033966,9525771,24045606, %U A096549 24045606,57862019,183002599,183002599,877875719,877875719,877875719,3789535319 %N A096549 Least exponent k such that the lowest n digits in the decimal representation of 2^k are even. %C A096549 This problem was discussed in a thread "Power of 2 with all even digits?" in the newsgroup sci.math (Jun 25 2004) with contributions from Edwin Clark, James Waldby, Bertram Felgenhauer, Richard Tobin, Oskar Lanzi III and others. %C A096549 a(47) > 15258789062500. - _Robert Xiao_, Mar 23 2025 %H A096549 Robert Xiao, <a href="/A096549/b096549.txt">Table of n, a(n) for n = 1..46</a> %H A096549 Newsgroup sci.math, <a href="http://mathforum.org/kb/message.jspa?messageID=581881">Power of 2 with all even digits?</a> %e A096549 a(5)=19 because 2^19=524288 is the smallest power of 2 that has a decimal representation ending in 5 even digits. %Y A096549 Cf. A000079, A068994. %K A096549 base,nonn %O A096549 1,2 %A A096549 _Hugo Pfoertner_, Jul 07 2004 %E A096549 a(21)-a(33) from Richard Tobin (richard(AT)cogsci.ed.ac.uk), Jun 29 2004