A317768 Number of nX3 0..1 arrays with every element unequal to 0, 1 or 3 horizontally, vertically or antidiagonally adjacent elements, with upper left element zero.

3, 4, 5, 11, 16, 28, 44, 74, 122, 209, 344, 584, 981, 1670, 2806, 4758, 8047, 13665, 23111, 39195, 66419, 112700, 190989, 323943, 549302, 931821, 1580102, 2680148, 4545629, 7710521, 13077362, 22181756, 37623572, 63817667, 108244170, 183603356

Offset

1,1

Comments

Column 3 of A317773.

Links

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

Formula

Empirical: a(n) = a(n-1) +6*a(n-4) -2*a(n-5) -11*a(n-8) -3*a(n-9) +6*a(n-12) +4*a(n-13) -a(n-16) -a(n-17) for n>23

Example

Some solutions for n=5
..0..0..0. .0..0..1. .0..1..1. .0..0..0. .0..0..0. .0..1..0. .0..0..0
..0..0..0. .0..0..0. .0..0..1. .1..0..0. .1..0..1. .0..1..1. .0..0..0
..0..0..0. .0..0..0. .0..0..0. .1..1..0. .1..0..1. .1..0..0. .0..0..0
..0..0..0. .0..0..0. .1..1..1. .1..1..1. .0..0..0. .0..0..0. .1..0..0
..0..0..0. .0..0..0. .0..1..1. .1..1..1. .0..0..0. .0..0..0. .1..1..0

Crossrefs

Cf. A317773.

Sequence in context: A067532 A276470 A152911 * A362665 A293713 A280255

Adjacent sequences: A317765 A317766 A317767 * A317769 A317770 A317771

Keyword

nonn

Author

R. H. Hardin, Aug 06 2018

Status

approved