A055537 Number of asymmetric types of (4,n)-hypergraphs under action of symmetric group S_4.

7, 64, 352, 1485, 5245, 16290, 45830, 119042, 289367, 664878, 1455136, 3051762, 6163153, 12033700, 22792660, 41997387, 75463460, 132510654, 227803866, 384031745, 635752338, 1034842530, 1658130458, 2617965384, 4076707044

Offset

3,1

Links

Table of n, a(n) for n=3..27.

Formula

G.f.: (1/(1-x)^16-6/(1-x)^8/(1-x^2)^4-3/(1-x)^4/(1-x^2)^6+8/(1-x)^4/(1-x^3)^4+2/(1-x)^2/(1-x^2)^3/(1-x^4)^2+6/(1-x)^4/(1-x^2)^4/(1-x^4)-8/(1-x)^2/(1-x^4)^2/(1-x^6))/24

Example

There are 7 asymmetric (4,3)-hypergraphs: {{1,2},{1,2,3},{1,3,4}}, {{1,2},{1,3},{1,2,4}}, {{1,2},{1,2},{1,3}}, {{1},{1,2},{1,2,3}}, {{1},{2,3},{1,2,4}}, {{1},{1,2},{2,3}}, {{1},{2},{1,3}}.

Crossrefs

Cf. A006148.

Sequence in context: A195630 A136955 A027767 * A333991 A159617 A098307

Adjacent sequences: A055534 A055535 A055536 * A055538 A055539 A055540

Keyword

nonn

Author

Vladeta Jovovic, Jul 09 2000

Extensions

More terms from James A. Sellers, Jul 11 2000

Status

approved