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 A368769 #19 May 11 2025 19:21:59
%S A368769 0,1,9,244,15617,1952126,421659217,144629111432,74050105053185,
%T A368769 53982526583771866,53982526583771866001,71850742883000353647332,
%U A368769 124158083701824611102589697,272775309892908670592389564310,748495450346141392105516964466641
%N A368769 a(n) = (n!)^3 * Sum_{k=1..n} 1/(k!)^3.
%F A368769 a(0) = 0; a(n) = n^3 * a(n-1) + 1.
%F A368769 a(n) = A217284(n) - (n!)^3.
%F A368769 a(n) ~ (A271574 - 1) * (n!)^3. - _Vaclav Kotesovec_, Jan 05 2024
%t A368769 Table[(n!)^3 Sum[1/(k!)^3,{k,n}],{n,0,20}] (* _Harvey P. Dale_, May 11 2025 *)
%o A368769 (PARI) a(n) = n!^3*sum(k=1, n, 1/k!^3);
%Y A368769 Cf. A368770, A368771, A368772.
%Y A368769 Cf. A002627, A066998.
%Y A368769 Cf. A217284, A271574.
%K A368769 nonn
%O A368769 0,3
%A A368769 _Seiichi Manyama_, Jan 04 2024