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 A305678 #8 Jun 11 2018 13:12:39 %S A305678 3,36,504,720,1404,19656,28080,44640,181440,195840,1740960,7637760, %T A305678 46085760,65862720,105960960,12884705280,16729130880,22826833920, %U A305678 38463828480,502503505920,890246522880,3377622411509760,131727274048880640,55340232208243752960,2158269056121506365440 %N A305678 Solutions x of uphi(x)/x = 2/3, where uphi is the unitary phi function (A047994). %C A305678 Apparently, these is a single x, 6, such that uphi(x)/x = 1/3. %H A305678 Tomohiro Yamada, <a href="https://arxiv.org/abs/1806.00647">An analog of perfect numbers involving the unitary totient function</a>, arXiv:1806.00647 [math.NT], 2018. %e A305678 uphi(3) = 2 so uphi(3)/3 = 2/3; %e A305678 uphi(36) = 24 so uphi(36)/36 = 2/3. %o A305678 (PARI) solve_uphi(2, 3, 10^40) \\ see A030163 %Y A305678 Cf. A047994 (uphi), A030163 (uphi(x)/x = 1/2). %K A305678 nonn %O A305678 1,1 %A A305678 _Michel Marcus_, Jun 08 2018