A256814 Number of length n+6 0..1 arrays with at most two downsteps in every 6 consecutive neighbor pairs.

120, 229, 442, 856, 1656, 3204, 6192, 11955, 23088, 44617, 86226, 166620, 321960, 622104, 1202016, 2322567, 4487848, 8671757, 16756074, 32377024, 62560664, 120883084, 233577104, 451331323, 872088416, 1685098737, 3256043394

Offset

1,1

Comments

Column 6 of A256816.

Links

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

Formula

Empirical: a(n) = 2*a(n-1) -a(n-2) +2*a(n-3) -a(n-4) +3*a(n-6) -2*a(n-7) -6*a(n-9) +4*a(n-10).

Empirical g.f.: x*(120 - 11*x + 104*x^2 - 39*x^3 + 48*x^4 + 93*x^5 - 190*x^6 - 128*x^7 - 250*x^8 + 252*x^9) / ((1 - x)*(1 - x - 2*x^3 - x^4 - x^5 - 4*x^6 - 2*x^7 - 2*x^8 + 4*x^9)). - Colin Barker, Jan 24 2018

Example

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

Crossrefs

Cf. A256816.

Sequence in context: A098565 A084142 A349745 * A232743 A146950 A028976

Adjacent sequences: A256811 A256812 A256813 * A256815 A256816 A256817

Keyword

nonn

Author

R. H. Hardin, Apr 10 2015

Status

approved