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 A066278 #10 Aug 24 2019 11:58:34
%S A066278 2,4,10,36,168,1008,7056,56448,470400,4704000,51528960,618347520,
%T A066278 7740902400,108372633600
%N A066278 Least solution to cototient(x) = n!, where cototient(x) = x-phi(x).
%C A066278 a(15) <= 1625589504000. a(16) <= 26009432064000. a(17) <= 442160345088000. [_Donovan Johnson_, Feb 05 2010]
%F A066278 a(n) = Min{x; x-A000010(x)=n!} = Min{A051953(x)=A000142(n)}.
%e A066278 Solutions to x-Phi[x]=720 are {1008,1424,1432,1436,1438} of which the smallest is a(6)=1008.
%o A066278 (PARI) a(n) = my(x=1); while(x-eulerphi(x) != n!, x++); x; \\ _Michel Marcus_, Aug 24 2019
%Y A066278 Cf. A000010, A051953, A000142, A055487.
%K A066278 nonn,more
%O A066278 1,1
%A A066278 _Labos Elemer_, Dec 10 2001
%E A066278 a(12)-a(14) from _Donovan Johnson_, Feb 05 2010