A318339 Number of nX4 0..1 arrays with every element unequal to 0, 1, 2 or 6 horizontally, vertically or antidiagonally adjacent elements, with upper left element zero.

8, 20, 36, 67, 148, 343, 817, 1975, 4788, 11644, 28327, 68949, 167840, 408591, 994711, 2421617, 5895464, 14352589, 34941627, 85066013, 207094729, 504175889, 1227425339, 2988189330, 7274801283, 17710636103, 43116865936, 104968794797

Offset

1,1

Comments

Column 4 of A318343.

Links

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

Formula

Empirical: a(n) = a(n-1) +4*a(n-2) +a(n-3) -5*a(n-4) -2*a(n-5) +2*a(n-6) +a(n-7) -a(n-8) for n>9

Example

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

Crossrefs

Cf. A318343.

Sequence in context: A265207 A004118 A082231 * A272730 A272738 A272782

Adjacent sequences: A318336 A318337 A318338 * A318340 A318341 A318342

Keyword

nonn

Author

R. H. Hardin, Aug 24 2018

Status

approved