

A215396


Number of lengthn 0..3 arrays connected endaround, 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
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OFFSET

1,4


COMMENTS



LINKS



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



KEYWORD

nonn


AUTHOR



STATUS

approved



