A255620 Number of length n+6 0..2 arrays with at most two downsteps in every 6 consecutive neighbor pairs

1647, 4248, 11386, 30816, 83325, 225253, 602886, 1605726, 4293918, 11529741, 30959919, 83094838, 222919389, 597525981, 1601258653, 4293585291, 11516774865, 30888797609, 82837467594, 222143245920, 595677211881, 1597318079838

Offset

1,1

Comments

Column 6 of A255622

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) +8*a(n-3) -9*a(n-4) +3*a(n-5) +46*a(n-6) -69*a(n-7) +27*a(n-8) -329*a(n-9) +354*a(n-10) -6*a(n-11) -395*a(n-12) +585*a(n-13) -216*a(n-14) +2590*a(n-15) -3837*a(n-16) +1548*a(n-17) -370*a(n-18) -69*a(n-19) -36*a(n-20)

Example

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

Crossrefs

Cf. A255622

Sequence in context: A349178 A247077 A093059 * A253030 A252684 A203864

Adjacent sequences: A255617 A255618 A255619 * A255621 A255622 A255623

Keyword

nonn

Author

R. H. Hardin, Feb 28 2015

Status

approved