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 A064031 #6 Jul 16 2019 06:15:46 %S A064031 1,1,1,576,207360000,26956124946896309452800000000000, %T A064031 2841003716170671644367609186370356458508919205193278721884160000000000000000000000 %N A064031 Product of non-unitary divisors of n!. %H A064031 Amiram Eldar, <a href="/A064031/b064031.txt">Table of n, a(n) for n = 1..10</a> %F A064031 a(n) = A061538(n!) = (n!)^(A048105(n!)/2) = (n!)^((A000005(n!)-A034444(n!))/2) %e A064031 n=6: 720 has 22 non-unitary divisors: a(6)=720^11=26956124946896309452800000000000 %t A064031 a[n_] := (n!)^(DivisorSigma[0, n!]/2 - 2^(PrimePi[n]-1)); Array[a, 10] (* _Amiram Eldar_, Jul 16 2019 *) %Y A064031 Cf. A048656, A048657, A061537, A061538, A000142, A048105, A000005, A034444. %K A064031 nonn %O A064031 1,4 %A A064031 _Labos Elemer_, Sep 13 2001