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 A292048 #10 Sep 15 2017 02:55:54 %S A292048 2,30,35070,36570,43230,159810,224610,331170,525630,1039890,1094730, %T A292048 1290810,1656930,1770510,2139990,4878390,5110710,5996310,6052530, %U A292048 6127890,7493430,9918930,10146570,12171810,12551370,13821870,21398370,23282130,25587030,30223830,31317510,31364970 %N A292048 Squarefree numbers n such that psi(phi(n)) = phi(psi(n) - n). %e A292048 30 = 2*3*5 is a term because psi(phi(30)) = phi(psi(30)-30). %e A292048 60 = 30*2 is not a term because it is not a squarefree number. %o A292048 (PARI) a001615(n) = my(f=factor(n)); prod(i=1, #f~, f[i, 1]^f[i, 2] + f[i, 1]^(f[i, 2]-1)); %o A292048 isok(n) = issquarefree(n) && a001615(eulerphi(n))==eulerphi(a001615(n)-n); \\ after _Charles R Greathouse IV_ at A001615 %Y A292048 Cf. A000010, A001615, A290002. %K A292048 nonn %O A292048 1,1 %A A292048 _Altug Alkan_, Sep 08 2017