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A215396
Number of length-n 0..3 arrays connected end-around, with no sequence of L<n elements immediately followed by itself (periodic "squarefree"), and new values introduced in order 0..3.
0
1, 1, 1, 3, 5, 17, 35, 102, 240, 665, 1661, 4501, 11466, 30366, 78990, 208272, 543065, 1427121, 3733443, 9798235, 25661293, 67307229, 176371866, 462472478
OFFSET
1,4
COMMENTS
Column 3 of A215401.
EXAMPLE
Some solutions for n=6:
..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....0....2....2....2....2....0....2....2....0....2....0....2
..3....3....1....3....2....0....0....1....1....2....0....0....2....3....2....0
..2....0....0....1....1....1....2....3....0....0....2....3....3....1....1....3
..1....2....2....3....3....3....3....2....3....3....1....1....2....2....2....2
CROSSREFS
Sequence in context: A148508 A148509 A148510 * A130844 A148511 A148512
KEYWORD
nonn
AUTHOR
R. H. Hardin, Aug 09 2012
STATUS
approved