A380242 Number of rooted 6-regular planar maps with n vertices.

1, 5, 100, 3000, 110000, 4550000, 204000000, 9690000000, 480700000000, 24667500000000, 1300650000000000, 70122000000000000, 3851316000000000000, 214878980000000000000, 12151776800000000000000, 695297229000000000000000, 40193385270000000000000000, 2344614140750000000000000000

Offset: 0

Author

Andrew Howroyd, Jan 22 2025

Keywords

• nonn

Links

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

Crossrefs

Column k=3 of A380241.

Cf. A000168, A380243.

Programs

PARI

a(n) = 2*10^n*(3*n)!/(n!*(2*n + 2)!)

Formula

a(n) = 2*10^n*(3*n)!/(n!*(2*n + 2)!).