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 A241906 #10 Jul 23 2021 03:20:34
%S A241906 1,2,3,8,18,42,102,248,611,1525,3845,9787,25118,64944,169047,442727,
%T A241906 1165990,3086692,8210400,21936230,58851484,158502600,428446818,
%U A241906 1162110731,3162318827,8631705612,23629386708,64865101678,178531867765,492622401009,1362567996602,3777490059587,10495626146222,29223682273897,81535625627546,227935763726546,638409001899851
%N A241906 a(n) = floor(bell(2n)/bell(n)^2), bell = A000110.
%C A241906 a(n) is the largest integer smaller than the (reciprocal) proportion of partitions of the set {1,..,2n} that refine the partition {1,..,n|n+1,..,2*n}.
%t A241906 Table[Floor[BellB[2*n]/BellB[n]^2], {n,0,30}] (* _Vaclav Kotesovec_, Jul 23 2021 *)
%o A241906 (GAP) QuoInt(Bell(2*n),Bell(n)^2)
%Y A241906 Cf. A000110.
%K A241906 nonn
%O A241906 0,2
%A A241906 _Nick Loughlin_, May 01 2014