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 A352658 #5 Apr 05 2022 17:08:55
%S A352658 1,1,5,39,508,9235,224481,6959932,266492388,12302514945,671505310855,
%T A352658 42664357009186,3114726872133570,258452373177094213,
%U A352658 24149855477595375815,2520813303733886387220,291892618561012451083816,37264133443594227118861233,5216461719269145457350349359
%N A352658 a(0) = 1; a(n) = (1/n) * Sum_{k=1..n} binomial(n,k)^2 * binomial(k+1,2) * k * a(n-k).
%F A352658 Sum_{n>=0} a(n) * x^n / n!^2 = exp( (x * BesselI(0,2*sqrt(x)) + sqrt(x) * BesselI(1,2*sqrt(x))) / 2 ).
%F A352658 Sum_{n>=0} a(n) * x^n / n!^2 = exp( Sum_{n>=1} binomial(n+1,2) * x^n / n!^2 ).
%t A352658 a[0] = 1; a[n_] := a[n] = (1/n) Sum[Binomial[n, k]^2 Binomial[k + 1, 2] k a[n - k], {k, 1, n}]; Table[a[n], {n, 0, 18}]
%t A352658 nmax = 18; CoefficientList[Series[Exp[(x BesselI[0, 2 Sqrt[x]] + Sqrt[x] BesselI[1, 2 Sqrt[x]])/2], {x, 0, nmax}], x] Range[0, nmax]!^2
%Y A352658 Cf. A000217, A002411, A023998, A279361, A336227, A337591.
%K A352658 nonn
%O A352658 0,3
%A A352658 _Ilya Gutkovskiy_, Mar 25 2022