A255105 Number of length n+6 0..2 arrays with at most one downstep in every 6 consecutive neighbor pairs

540, 1008, 2032, 4338, 9297, 19263, 38010, 73278, 143045, 288057, 594045, 1228136, 2495244, 4970793, 9823140, 19533636, 39362880, 80112560, 163010352, 329127561, 659192991, 1316427636, 2637095196, 5313657069, 10747592751, 21727946097

Offset

1,1

Comments

Column 6 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) +25*a(n-6) -42*a(n-7) +18*a(n-8) -10*a(n-12) +6*a(n-13)

Example

Some solutions for n=4
..0....1....0....1....1....0....2....0....1....2....1....1....0....1....0....0
..2....0....0....2....1....0....0....1....0....0....1....1....0....1....1....1
..0....0....2....0....2....0....1....1....0....0....2....0....0....1....2....1
..0....1....2....0....0....1....1....0....0....0....1....0....1....2....0....0
..1....1....2....0....0....1....2....0....0....0....1....1....1....1....0....0
..2....1....0....1....1....0....2....0....0....0....1....2....1....1....0....1
..2....1....0....2....1....0....2....0....1....0....1....2....2....1....0....1
..2....1....1....2....1....0....2....1....2....1....1....2....2....1....1....2
..2....1....1....0....1....1....0....1....2....0....1....0....1....2....2....2
..0....2....2....0....2....2....0....2....0....0....0....1....2....2....1....1

Crossrefs

Cf. A255107

Sequence in context: A345390 A261290 A253463 * A298685 A185463 A069474

Adjacent sequences: A255102 A255103 A255104 * A255106 A255107 A255108

Keyword

nonn

Author

R. H. Hardin, Feb 14 2015

Status

approved