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 A338439 #4 Oct 28 2020 09:29:25
%S A338439 1,1,0,3,8,50,144,2394,8448,89424,576000,20124720,57231360,3213905760,
%T A338439 11285084160,217204092000,2843121254400,187660890063360,
%U A338439 558255985459200,64849189355274240,239933887119360000,8405611881201561600,116110668405473280000,13912098832249673932800
%N A338439 a(n) = n! * [x^n] Product_{k=1..n, gcd(n,k) = 1} (1 + x^k/k).
%t A338439 Table[n! SeriesCoefficient[Product[(1 + Boole[GCD[n, k] == 1] x^k/k), {k, 1, n}], {x, 0, n}], {n, 0, 23}]
%Y A338439 Cf. A007838, A036998, A338437.
%K A338439 nonn
%O A338439 0,4
%A A338439 _Ilya Gutkovskiy_, Oct 27 2020