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 A346410 #5 Jul 15 2021 21:21:20
%S A346410 0,1,5,22,152,2001,45097,1527506,71864928,4466430513,353828600029,
%T A346410 34770661312190,4148422395161464,590479899466175681,
%U A346410 98824492409739430401,19209838771051338898234,4291488438323868507946880,1091819942877526843993466529,313819508664449992611846900981
%N A346410 a(n) = (n!)^2 * Sum_{k=0..n-1} 1 / ((n-k) * k!)^2.
%F A346410 Sum_{n>=0} a(n) * x^n / (n!)^2 = polylog(2,x) * BesselI(0,2*sqrt(x)).
%t A346410 Table[(n!)^2 Sum[1/((n - k) k!)^2, {k, 0, n - 1}], {n, 0, 18}]
%t A346410 nmax = 18; CoefficientList[Series[PolyLog[2, x] BesselI[0, 2 Sqrt[x]], {x, 0, nmax}], x] Range[0, nmax]!^2
%Y A346410 Cf. A002104, A006040, A066998, A193563, A336291, A346411.
%K A346410 nonn
%O A346410 0,3
%A A346410 _Ilya Gutkovskiy_, Jul 15 2021