A303867 Number of noncrossing path sets on 4*n nodes up to rotation and reflection with each path having exactly 4 nodes.

1, 2, 21, 494, 18086, 794696, 38695548, 2015556488, 110292751866, 6267709291736, 367003473639464, 22018423100856184, 1347856204419978236, 83918845269760695536, 5300972002005297517812, 339058084617031980524000, 21924124400037221008705338, 1431303944222490626674244672

Offset

0,2

Links

Andrew Howroyd, Table of n, a(n) for n = 0..200

Math StackExchange, Question from user Matan at math.stackexchange.com: Number of ways to connect sets of k dots in a perfect n-gon

Formula

a(n) ~ 2^(11*n - 5/2) / (sqrt(Pi) * n^(5/2) * 3^(3*n + 3/2)). - Vaclav Kotesovec, Jun 01 2022

Crossrefs

Column 4 of A302828.

Cf. A303330, A303839, A303866.

Sequence in context: A192666 A090451 A199747 * A238696 A226057 A158886

Adjacent sequences: A303864 A303865 A303866 * A303868 A303869 A303870

Keyword

nonn

Author

Andrew Howroyd, May 01 2018

Status

approved