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A303867
Number of noncrossing path sets on 4*n nodes up to rotation and reflection with each path having exactly 4 nodes.
4
1, 2, 21, 494, 18086, 794696, 38695548, 2015556488, 110292751866, 6267709291736, 367003473639464, 22018423100856184, 1347856204419978236, 83918845269760695536, 5300972002005297517812, 339058084617031980524000, 21924124400037221008705338, 1431303944222490626674244672
OFFSET
0,2
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.
Sequence in context: A090451 A199747 A377889 * A238696 A226057 A158886
KEYWORD
nonn
AUTHOR
Andrew Howroyd, May 01 2018
STATUS
approved