%I #19 Jan 25 2024 19:11:31
%S 0,2,3,4,4,3,5,4,5,5,5,4,6,5,5,5,7,5,6,5,6,6,6,4,5,6,6,6,7,5,7,6,6,7,
%T 6,6,6,6,7,5,7,6,7,6,6,7,7,6,7,7,7,6,7,6,7,7,6,7,8,5,6,7,7,6,7,6,7,7,
%U 7,6,7,6,7,7,6,6,7,7,7,6,7,7,8,6,8,7,7,7,8,6,7,7,7,7,7,6,8,7,7,7,7,7
%N The minimum size of a poset having n linear extensions.
%H François Labelle, <a href="/A160371/b160371.txt">Table of n, a(n) for n = 1..1000</a>
%H Swee Hong Chan and Igor Pak, <a href="https://arxiv.org/abs/2308.10214">Computational complexity of counting coincidences</a>, arXiv:2308.10214 [math.CO], 2023. See p. 12.
%H Swee Hong Chan and Igor Pak, <a href="https://arxiv.org/abs/2401.09723">Linear extensions and continued fractions</a>, arXiv:2401.09723 [math.CO], 2024.
%H Bridget E. Tenner, <a href="http://arxiv.org/abs/0905.1688">Optimizing linear extensions</a>, arXiv:0905.1688 [math.CO], 2009; SIAM J. Discr. Math. 23 (2009) 1450-1454.
%F a(n) <= 2*sqrt(n).
%e a(5) = 4 because the poset with two minimal elements, two maximal elements, and three covering relations between them ["N" shaped] has exactly 5 linear extensions and 4 elements. No smaller poset has 5 linear extensions.
%Y Cf. A263860.
%Y Cf. A281723 for the smallest index n = A281723(m) such that a(n) > m.
%K nonn
%O 1,2
%A _Bridget Tenner_, May 11 2009
%E a(13)-a(102) from _François Labelle_, Jan 28 2017