A361240 Number of nonequivalent noncrossing triangular cacti with n triangles up to rotation and reflection.

1, 1, 1, 4, 19, 124, 931, 7801, 68685, 630850, 5966610, 57808920, 571178751, 5737672339, 58455577800, 602859484608, 6283968796705, 66119472527814, 701526880303315, 7498841163925819, 80696081185766970, 873654670250482120, 9510760874015305314, 104056578392127906720

Offset: 0

Author

Andrew Howroyd, Mar 06 2023

Keywords

• nonn

Links

• Andrew Howroyd, Table of n, a(n) for n = 0..500

Crossrefs

Column 3 of A361239.

Cf. A002294, A118970, A361237.

Formula

a(2*n) = (A361237(2*n) + A002294(n))/2; a(2*n+1) = (A361237(2*n+1) + A118970(n))/2.