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 A358279 #17 Aug 30 2023 02:00:43
%S A358279 1,3,7,29,121,747,5041,40433,362935,3629433,39916801,479006531,
%T A358279 6227020801,87178326609,1307674371487,20922790212353,355687428096001,
%U A358279 6402373709021811,121645100408832001,2432902008212950169,51090942171709691335,1124000727778046766849
%N A358279 a(n) = Sum_{d|n} (d-1)! * d^(n/d).
%F A358279 G.f.: Sum_{k>0} k! * x^k/(1 - k * x^k).
%F A358279 If p is prime, a(p) = 1 + p!.
%t A358279 a[n_] := DivisorSum[n, (# - 1)! * #^(n/#) &]; Array[a, 22] (* _Amiram Eldar_, Aug 30 2023 *)
%o A358279 (PARI) a(n) = sumdiv(n, d, (d-1)!*d^(n/d));
%o A358279 (PARI) my(N=30, x='x+O('x^N)); Vec(sum(k=1, N, k!*x^k/(1-k*x^k)))
%Y A358279 Cf. A038507, A062363, A078308, A217576, A321521, A358280.
%K A358279 nonn,easy
%O A358279 1,2
%A A358279 _Seiichi Manyama_, Nov 08 2022