A215399 Number of length-n 0..6 arrays connected end-around, with no sequence of L<n elements immediately followed by itself (periodic "squarefree"), and new values introduced in order 0..6.

1, 1, 1, 3, 6, 27, 99, 462, 2205, 11414, 61028, 337089, 1894854, 10794718, 61989059, 357903580, 2073376576, 12037807836

Offset

1,4

Comments

Column 6 of A215401.

Links

Table of n, a(n) for n=1..18.

Example

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....3....3....3....3....3....1....1....1....3....1....1....3....3....3....3
..4....4....4....4....2....4....3....3....3....4....3....3....4....0....1....4
..0....1....5....0....4....1....4....2....4....2....4....1....2....1....2....0
..2....2....0....2....1....5....0....4....3....0....0....4....4....3....4....5
..1....5....4....4....0....4....5....3....1....3....3....0....3....4....5....4
..3....3....6....3....4....5....4....5....4....5....1....5....4....5....1....6

Crossrefs

Sequence in context: A023169 A083695 A215398 * A215400 A215394 A222625

Adjacent sequences: A215396 A215397 A215398 * A215400 A215401 A215402

Keyword

nonn

Author

R. H. Hardin, Aug 09 2012

Status

approved