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 A217238 #16 Jul 12 2022 08:40:16
%S A217238 0,1,6,54,792,18360,628560,29801520,1864114560,148458925440,
%T A217238 14652778694400,1754531487878400,250496910657100800,
%U A217238 42032247882174950400,8188505926902446745600,1832839841627736125184000,467088574163438830546944000
%N A217238 a(n) = n! * Sum_{k=1..n} k!.
%C A217238 Variant of A143217.
%H A217238 Vincenzo Librandi, <a href="/A217238/b217238.txt">Table of n, a(n) for n = 0..200</a>
%F A217238 a(n) = n!*(!(n+1) - 1).
%F A217238 a(n) = A000142(n) * A007489(n).
%t A217238 Table[n!*Sum[i!, {i, n}], {n, 0, 16}]
%o A217238 (Magma) [0] cat [Factorial(n)*&+[Factorial(k) : k in [1..n]] : n in [1..20]]; // _Wesley Ivan Hurt_, Jul 03 2020
%o A217238 (SageMath) f=factorial; [f(n)*sum(f(k) for k in (1..n)) for n in (0..40)] # _G. C. Greubel_, Jul 12 2022
%Y A217238 Cf. A000142, A007489, A061640, A143217, A217239.
%K A217238 nonn,easy
%O A217238 0,3
%A A217238 _Olivier Gérard_, Sep 28 2012