A222421 Number of unlabeled 3-uniform directed hypergraphs of order n.

1, 1, 4, 218, 8978144, 1601285885249024, 8048575244466823237217930240

Offset

1,3

Links

Table of n, a(n) for n=1..7.

J. Qian, Enumeration of unlabeled directed hypergraphs, Electronic Journal of Combinatorics, 20(1) (2013), #P46.

Crossrefs

Cf. A000273, A222420.

Sequence in context: A248099 A068210 A078693 * A025420 A259460 A227822

Adjacent sequences: A222418 A222419 A222420 * A222422 A222423 A222424

Keyword

nonn,more

Author

N. J. A. Sloane, Mar 01 2013

Status

approved