A049313 Switching classes of tournaments on n nodes.

1, 1, 1, 2, 2, 6, 12, 79, 792, 19576, 886288, 75369960, 11856006240, 3467430423264, 1893448825054528, 1938818712501985736, 3737086626658278741376, 13606268915761294708760704, 93863103860384959101157737728

Offset: 1

Author

Peter J. Cameron

Keywords

• nonn
• nice

Examples

			a(4)=2: the "local orders" form one switching class and the class containing a 3-cycle dominating a point the other.
		

Links

• L. Babai and P. J. Cameron, Automorphisms and enumeration of switching classes of tournaments, Electron. J. Combin., 7 (2000), no. 1, Research Paper 38, 25 pp.
• P. J. Cameron, Sequences realized by oligomorphic permutation groups, J. Integ. Seqs. Vol. 3 (2000), #00.1.5.

Crossrefs

Cf. A002854.

Formula

Same as for switching classes of graphs but summed only over "level" permutations (same power of 2 divides all cycle lengths)

Extensions

More terms from Vladeta Jovovic, Mar 01 2000