A055536 Number of asymmetric types of (3,n)-hypergraphs under action of symmetric group S_3.

1, 8, 29, 82, 198, 426, 841, 1556, 2726, 4568, 7373, 11522, 17507, 25958, 37658, 53582, 74924, 103130, 139938, 187426, 248044, 324678, 420698, 540014, 687141, 867274, 1086343, 1351108, 1669234, 2049376, 2501275, 3035866, 3665362

Offset

2,2

Links

Table of n, a(n) for n=2..34.

Formula

G.f.: (1/(1-x)^8-3/(1-x)^4/(1-x^2)^2+2/(1-x)^2/(1-x^3)^2)/6.

Example

There are 8 asymmetric (3,3)-hypergraphs: {{1,2},{1,2},{1,3}}, {{1},{1,2},{1,2,3}}, {{1},{1,2},{1,2}}, {{1},{1},{1,2}}, {{1},{1,2},{2,3}}, {{1},{2},{1,3}}, {{1},{1},{2}}, {0,{1},{1,2}}.

Crossrefs

Cf. A002727.

Sequence in context: A028419 A046664 A333510 * A131438 A048478 A001360

Adjacent sequences: A055533 A055534 A055535 * A055537 A055538 A055539

Keyword

nonn

Author

Vladeta Jovovic, Jul 09 2000

Extensions

More terms from James A. Sellers, Jul 11 2000

Status

approved