A255106 Number of length n+7 0..2 arrays with at most one downstep in every 7 consecutive neighbor pairs

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

R. H. Hardin, Table of n, a(n) for n = 1..210

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

Cf. A255107

Sequence in context: A152503 A099688 A257485 * A253039 A237229 A219526

Adjacent sequences: A255103 A255104 A255105 * A255107 A255108 A255109

Keyword

nonn

Author

R. H. Hardin, Feb 14 2015

Status

approved