A208534 Number of n-bead necklaces of 7 colors not allowing reversal, with no adjacent beads having the same color.

7, 21, 70, 336, 1554, 7826, 39990, 210126, 1119790, 6047412, 32981550, 181402676, 1004668770, 5597460306, 31345666730, 176319474366, 995685849690, 5642220380006, 32071565263710, 182807925027504

Offset: 1

Author

R. H. Hardin, Feb 27 2012

Keywords

• nonn

Examples

			Some solutions for n=4
..1....1....2....3....3....1....1....2....1....3....1....3....4....1....1....1
..3....5....3....5....5....6....3....7....5....7....4....7....7....2....3....5
..1....7....4....6....3....1....4....4....7....6....3....5....5....4....6....4
..5....2....3....7....7....6....5....3....6....4....2....4....6....7....2....2
		

Crossrefs

Column 7 of A208535.