A256815 Number of length n+7 0..1 arrays with at most two downsteps in every 7 consecutive neighbor pairs

219, 402, 753, 1424, 2693, 5088, 9613, 18104, 34013, 63928, 120362, 226816, 427341, 804974, 1516179, 2855304, 5376354, 10123582, 19065294, 35907400, 67626166, 127359488, 239852341, 451704432, 850669960, 1602023036, 3017039568

Offset

1,1

Comments

Column 7 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) +3*a(n-4) -2*a(n-5) +10*a(n-7) -7*a(n-8) -12*a(n-11) +9*a(n-12) -24*a(n-14) +18*a(n-15)

Example

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

Crossrefs

Cf. A256816

Sequence in context: A025404 A361343 A192086 * A179580 A043435 A166836

Adjacent sequences: A256812 A256813 A256814 * A256816 A256817 A256818

Keyword

nonn

Author

R. H. Hardin, Apr 10 2015

Status

approved