A256813 Number of length n+5 0..1 arrays with at most two downsteps in every 5 consecutive neighbor pairs.

63, 124, 245, 484, 956, 1888, 3728, 7362, 14539, 28712, 56701, 111974, 221128, 436688, 862380, 1703044, 3363203, 6641716, 13116185, 25902088, 51151928, 101015784, 199487860, 393952358, 777984487, 1536378320, 3034068649

Offset

1,1

Comments

Column 5 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) +2*a(n-5) -a(n-6).

Empirical g.f.: x*(63 - 2*x + 60*x^2 - 8*x^3 + 48*x^4 - 32*x^5) / (1 - 2*x + x^2 - 2*x^3 + x^4 - 2*x^5 + x^6). - Colin Barker, Jan 24 2018

Example

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

Crossrefs

Cf. A256816.

Sequence in context: A274460 A181556 A096023 * A324488 A080947 A023720

Adjacent sequences: A256810 A256811 A256812 * A256814 A256815 A256816

Keyword

nonn

Author

R. H. Hardin, Apr 10 2015

Status

approved