A215400 Number of length-n 0..7 arrays connected end-around, with no sequence of L<n elements immediately followed by itself (periodic "squarefree"), and new values introduced in order 0..7.

1, 1, 1, 3, 6, 27, 99, 463, 2232, 11839, 66176, 390465, 2394678, 15154985, 98121614, 646053822, 4304919741, 28930077597

Offset

1,4

Comments

Column 7 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....0....2....0....2....2....2....2
..1....3....3....0....3....3....3....3....1....2....3....2....3....3....3....0
..3....1....1....3....4....4....4....4....3....1....1....3....1....4....4....3
..2....3....4....4....1....1....1....2....4....2....4....0....3....1....0....1
..1....2....5....3....3....5....5....4....5....3....1....2....4....4....2....3
..2....4....6....2....2....4....0....0....3....1....2....1....0....5....0....4
..4....5....3....1....5....2....2....2....6....2....1....4....5....1....5....1

Crossrefs

Sequence in context: A083695 A215398 A215399 * A215394 A222625 A060170

Adjacent sequences: A215397 A215398 A215399 * A215401 A215402 A215403

Keyword

nonn

Author

R. H. Hardin, Aug 09 2012

Status

approved