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 A253901 #13 Oct 13 2017 21:38:43
%S A253901 1,1,2,6,24,60,720,840,20160,15120,3628800,55440,479001600,8648640,
%T A253901 1816214400,259459200,20922789888000,147026880,6402373705728000,
%U A253901 55870214400,1689515283456000,14079294028800,1124000727777607680000,771008958720,25852016738884976640000,32382376266240000,10002268381116211200000
%N A253901 a(n) = Product_{d divides n} ((d-1)!)^moebius(n/d).
%F A253901 (n-1)! = Product_{d divides n} a(d).
%o A253901 (PARI) a(n)={my(r=1);fordiv(n,d,r*=((d-1)!)^moebius(n/d));r}
%Y A253901 Cf. A250269: Product_{d divides n} (d!)^moebius(n/d).
%K A253901 nonn
%O A253901 1,3
%A A253901 _Joerg Arndt_, Jan 18 2015