%I #20 Jul 18 2022 13:13:41
%S 0,0,1,2,6,19,80,395,2487,19890,206565,2804453,49872647,1158843214,
%T 35049606566,1374685228988,69690886873398,4554367168841547
%N Number of unlabeled disconnected posets with n elements.
%H Gunnar Brinkmann and Brendan D. McKay, <a href="http://users.cecs.anu.edu.au/~bdm/papers/posets.pdf">Posets on up to 16 points</a>.
%H Salah Uddin Mohammad, Md. Shah Noor, and Md. Rashed Talukder, <a href="https://cs.uwaterloo.ca/journals/JIS/VOL25/Uddin/uddin6.html">An Exact Enumeration of the Unlabeled Disconnected Posets</a>, J. Int. Seq., Vol. 25 (2022), Article 22.5.4.
%F a(n) = A000112(n) - A000608(n).
%Y Cf. A000112, A000608, A342500.
%K nonn,more
%O 0,4
%A _Salah Uddin Mohammad_, Nov 15 2021