A293501 Number of unlabeled semiorders on n points and having dimension 3.

3, 40, 318, 1974, 10603, 51894, 238413, 1047440, 4454826, 18496217, 75416600, 303287250, 1206781482, 4762466651, 18674965709, 72866587238, 283217927396, 1097537249485, 4243554109115, 16379413110981, 63142882465324, 243203630272390

Offset: 7

Author

Mitchel T. Keller, Oct 10 2017

Keywords

• nonn

Links

• Mitchel T. Keller, Stephen J. Young, Hereditary Semiorders and Enumeration of Semiorders by Dimension, arXiv:1801.00501 [math.CO], 2018.

Crossrefs

Cf. A000108, A293498.

Formula

a(n) = A000108(n) - A293498(n).