A222420 Number of unlabeled general directed hypergraphs of order n.

2, 10, 752, 179228736, 10074382205972351614976

Offset

1,1

Links

Table of n, a(n) for n=1..5.

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

Example

The 10 non-isomorphic directed hypergraphs of order 2 are as follows (these are their arc sets): {<1,0>, <2,0>}, {<1, {2}>, <2, {1}>}, {<1, {2}>, <1,0>, <2, {1}>, <2,0>}, {<1, {2}>}, {<1, {2}>, <1,0>}, {<1, {2}>, <1,0>, <2, {1}>}, {<1,0>}, {<1, {2}>, <2,0>}, {<1, {2}>, <1,0>, <2,0>}, 0.

Crossrefs

Cf. A000273, A222421.

Sequence in context: A089500 A246628 A028582 * A263921 A290495 A255587

Adjacent sequences: A222417 A222418 A222419 * A222421 A222422 A222423

Keyword

nonn,more

Author

N. J. A. Sloane, Mar 01 2013

Status

approved