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 A123476 #10 Jul 11 2018 04:38:11
%S A123476 1,4,18,72,450,2700,22050,176400,1587600,15876000,192099600,
%T A123476 2305195200,32464832400,454507653600,6817614804000,109081836864000,
%U A123476 1970290678356000,35465232210408000,711274934886516000
%N A123476 a(n) = (n!)^2/phi(n!), where phi is Euler's totient function.
%C A123476 a(n) is a solution to the equation phi(x) = n!.
%H A123476 T. D. Noe, <a href="/A123476/b123476.txt">Table of n, a(n) for n=1..100</a>
%H A123476 P. Erdos and J. Lambek, <a href="https://www.jstor.org/stable/2305755">Problem 4221</a>, Amer. Math. Monthly, 55 (1948), 103.
%t A123476 Table[(n!)^2/EulerPhi[n!],{n,20}] (* _Harvey P. Dale_, Nov 29 2015 *)
%o A123476 (PARI) a(n) = (n!)^2/eulerphi(n!); \\ _Michel Marcus_, Jul 11 2018
%Y A123476 Cf. A000010, A000142, A002202 (values taken by phi(x)).
%Y A123476 Cf. A055487 (least m such that phi(m) = n!).
%K A123476 nonn
%O A123476 1,2
%A A123476 _T. D. Noe_, Sep 27 2006