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A255106
Number of length n+7 0..2 arrays with at most one downstep in every 7 consecutive neighbor pairs
1
927, 1616, 3042, 6141, 12662, 25578, 49611, 91887, 166290, 303969, 573853, 1118256, 2210103, 4340001, 8343339, 15695433, 29216435, 54612816, 103548108, 199304393, 386593848, 747736983, 1432037309, 2714684340, 5119381929, 9669662693
OFFSET
1,1
COMMENTS
Column 7 of A255107
LINKS
FORMULA
Empirical: a(n) = 3*a(n-1) -3*a(n-2) +a(n-3) +33*a(n-7) -57*a(n-8) +25*a(n-9) -15*a(n-14) +10*a(n-15)
EXAMPLE
Some solutions for n=4
..0....2....1....0....0....2....1....0....0....0....0....0....1....1....0....0
..1....2....1....0....2....2....1....1....0....1....1....1....0....2....0....0
..1....1....1....0....0....1....1....2....0....0....2....2....0....2....1....0
..1....2....0....1....0....1....1....0....0....0....2....0....1....2....1....0
..2....2....1....1....1....1....1....0....0....0....0....0....1....2....0....1
..2....2....1....1....1....1....2....0....1....1....0....0....1....2....0....1
..2....2....1....1....2....1....0....0....1....1....0....0....1....0....0....2
..1....2....2....1....2....1....1....0....1....2....0....0....1....2....0....2
..1....2....2....1....2....1....1....0....0....2....1....1....2....2....0....2
..1....2....2....1....2....2....1....0....2....1....2....2....0....2....1....2
..2....0....0....1....0....0....2....1....2....2....2....1....2....2....1....1
CROSSREFS
Sequence in context: A152503 A099688 A257485 * A253039 A237229 A219526
KEYWORD
nonn
AUTHOR
R. H. Hardin, Feb 14 2015
STATUS
approved