A215074 Number of squarefree words of length n in an 8-ary alphabet, with new values 0..7 introduced in increasing order.

1, 1, 2, 4, 12, 40, 154, 660, 3113, 15893, 86857, 502092, 3036032, 19006591, 122119857, 799665333, 5308126648, 35576413852, 240063646519, 1627605038848

Offset: 1

Author

R. H. Hardin Aug 02 2012

Keywords

• nonn

Comments

Column 7 of A215075.

Examples

			Some solutions for n=9:
..0....0....0....0....0....0....0....0....0....0....0....0....0....0....0....0
..1....1....1....1....1....1....1....1....1....1....1....1....1....1....1....1
..2....2....2....2....2....2....2....2....2....2....2....2....2....2....2....2
..3....0....1....3....1....3....3....1....3....3....0....3....1....1....3....0
..4....3....3....4....3....4....4....3....4....0....3....4....3....3....4....3
..0....1....1....5....4....5....1....0....2....2....4....5....4....0....0....4
..3....4....0....4....0....4....5....4....5....4....5....6....0....1....1....0
..1....2....4....0....2....1....3....2....0....5....1....7....5....0....0....5
..2....0....1....6....3....2....0....5....1....4....6....2....1....3....5....2