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 A327030 #28 Sep 08 2022 08:46:24
%S A327030 0,1,3,8,28,124,732,5046,40352,362898,3628932,39916810,479002388,
%T A327030 6227020812,87178296258,1307674368272,20922789928384,355687428096016,
%U A327030 6402373706092350,121645100408832018,2432902008180269152,51090942171709450128,1124000727777647596830
%N A327030 a(n) = Sum_{d|n} phi(d)*(n/d)! for n > 0, a(0) = 0.
%C A327030 Dirichlet convolution of phi(n) and n! (n >= 1). - _Richard L. Ollerton_, May 09 2021
%H A327030 Seiichi Manyama, <a href="/A327030/b327030.txt">Table of n, a(n) for n = 0..449</a>
%F A327030 a(n) = Sum_{i=1..n} gcd(n,i)!. - _Ridouane Oudra_, Nov 13 2019
%p A327030 with(numtheory); A327030 := n -> add(phi(d)*(n/d)!, d = divisors(n)):
%p A327030 seq(A327030(n), n=0..22);
%t A327030 a[0] = 0; a[n_] := DivisorSum[n, EulerPhi[#] * (n/#)! &]; Array[a, 23, 0] (* _Amiram Eldar_, May 24 2021 *)
%o A327030 (PARI) a(n) = if (n>0, sumdiv(n, d, eulerphi(d)*(n/d)!), 0); \\ _Michel Marcus_, Aug 28 2019
%o A327030 (Magma) [0] cat [&+[EulerPhi(d)*Factorial(n div d):d in Divisors(n)]:n in [1..22]]; // _Marius A. Burtea_, Nov 13 2019
%o A327030 (Magma) [0] cat [&+[Factorial(Gcd(n,i)):i in [1..n]]:n in [1..22]]; // _Marius A. Burtea_, Nov 13 2019
%Y A327030 Cf. A000010, A000142, A027750.
%Y A327030 Similar: A078392 (numbpart), A258171 (bell), A053635 (numbcomb), A181847 and A034738 (numbcomp), this sequence (numbperm).
%K A327030 nonn
%O A327030 0,3
%A A327030 _Peter Luschny_, Aug 27 2019