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 A063469 #14 Dec 15 2017 17:35:21 %S A063469 7,21,26,56,70,78,108,126,168,210 %N A063469 Numbers n such that tau(n)*3 = phi(n). %C A063469 "phi(n)=k*Tau[n] has at most finitely many solutions for any constant k or even for slowly increasing functions like k(n)=n^(epsilon)." - _Labos Elemer_, Jul 20 2001 %t A063469 Select[Range[300],3DivisorSigma[0,#]==EulerPhi[#]&] (* _Harvey P. Dale_, Sep 15 2016 *) %o A063469 (PARI) for(n=1,10^7, if(3*numdiv(n)==eulerphi(n),print(n))) %Y A063469 Cf. A062516. %Y A063469 Cf. A112954, A020488, A063470. %K A063469 fini,full,nonn %O A063469 1,1 %A A063469 _Jason Earls_, Jul 26 2001 %E A063469 "full" keyword from _Max Alekseyev_, Mar 01 2010