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 A339311 #16 Apr 28 2021 02:04:15
%S A339311 1,5,225,333089,24891170433,139317055679149697,
%T A339311 82606511560391889386751489,6984964663477899063759529684476994049,
%U A339311 109110688697205077023425816926479750793809817618433,395940866162019279867473563258123776010342586429441374123441432577
%N A339311 a(n) = Sum_{k=1..n} (k!)^n.
%H A339311 Seiichi Manyama, <a href="/A339311/b339311.txt">Table of n, a(n) for n = 1..30</a>
%t A339311 a[n_] := Sum[(k!)^n, {k, 1, n}]; Array[a, 10] (* _Amiram Eldar_, Apr 28 2021 *)
%o A339311 (PARI) {a(n) = sum(k=1, n, k!^n)}
%Y A339311 Sum_{k=1..n} (k!)^m: A007489 (m=1), A104344 (m=2), A138564 (m=3), A289945 (m=4), A316777 (m=5), A289946 (m=6).
%Y A339311 Cf. A000142, A112999.
%K A339311 nonn
%O A339311 1,2
%A A339311 _Seiichi Manyama_, Nov 29 2020