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 A346655 #11 Aug 03 2021 21:36:18
%S A346655 1,5,2430,5597643,35618229364,483040313859705,11977437107679230274,
%T A346655 490630568583958198181583,30889771581097736768046865352,
%U A346655 2832037863467651034046820871428061,362579939205426756198837321528946171110,62687814132880422794200073791149602981717667
%N A346655 a(n) = Bell(3*n,n).
%C A346655 In general, for k>=1, Bell(k*n,n) ~ (k*n/LambertW(k))^(k*n) / (sqrt(1 + LambertW(k)) * exp(n*(k + 1 - k/LambertW(k)))).
%H A346655 Alois P. Heinz, <a href="/A346655/b346655.txt">Table of n, a(n) for n = 0..137</a>
%F A346655 a(n) ~ (3*n/LambertW(3))^(3*n) / (sqrt(1 + LambertW(3)) * exp(n*(4 - 3/LambertW(3)))).
%F A346655 a(n) = A189233(3n,n) = A292860(3n,n). - _Alois P. Heinz_, Jul 27 2021
%p A346655 b:= proc(n, k) option remember; `if`(n=0, 1,
%p A346655 (1+add(binomial(n-1, j-1)*b(n-j, k), j=1..n-1))*k)
%p A346655 end:
%p A346655 a:= n-> b(3*n, n):
%p A346655 seq(a(n), n=0..11); # _Alois P. Heinz_, Jul 27 2021
%t A346655 Table[BellB[3*n, n], {n, 0, 15}]
%Y A346655 Cf. A000110, A189233, A242817, A292860, A346654.
%K A346655 nonn
%O A346655 0,2
%A A346655 _Vaclav Kotesovec_, Jul 27 2021