%I #10 Jun 01 2022 06:13:02
%S 1,2,21,494,18086,794696,38695548,2015556488,110292751866,
%T 6267709291736,367003473639464,22018423100856184,1347856204419978236,
%U 83918845269760695536,5300972002005297517812,339058084617031980524000,21924124400037221008705338,1431303944222490626674244672
%N Number of noncrossing path sets on 4*n nodes up to rotation and reflection with each path having exactly 4 nodes.
%H Andrew Howroyd, <a href="/A303867/b303867.txt">Table of n, a(n) for n = 0..200</a>
%H Math StackExchange, <a href="https://math.stackexchange.com/questions/1294224/">Question from user Matan at math.stackexchange.com: Number of ways to connect sets of k dots in a perfect n-gon</a>
%F a(n) ~ 2^(11*n - 5/2) / (sqrt(Pi) * n^(5/2) * 3^(3*n + 3/2)). - _Vaclav Kotesovec_, Jun 01 2022
%Y Column 4 of A302828.
%Y Cf. A303330, A303839, A303866.
%K nonn
%O 0,2
%A _Andrew Howroyd_, May 01 2018