A300641 Number of nX3 0..1 arrays with every element equal to 2, 3, 4 or 5 horizontally, vertically or antidiagonally adjacent elements, with upper left element zero.

0, 2, 2, 10, 30, 104, 340, 1144, 3795, 12683, 42227, 140876, 469517, 1565586, 5219130, 17400850, 58012053, 193409644, 644810491, 2149754855, 7167115016, 23894640479, 79662932803, 265590322328, 885458314722, 2952052210282, 9841922224851

Offset

1,2

Comments

Column 3 of A300646.

Links

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

Formula

Empirical: a(n) = 2*a(n-1) +4*a(n-2) -a(n-3) +7*a(n-4) +6*a(n-5) -2*a(n-6) -7*a(n-7) -11*a(n-8) -12*a(n-9) -8*a(n-10) -9*a(n-11) -3*a(n-12) -2*a(n-14) +a(n-15)

Example

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

Crossrefs

Cf. A300646.

Sequence in context: A151364 A200949 A001885 * A078433 A059494 A052647

Adjacent sequences: A300638 A300639 A300640 * A300642 A300643 A300644

Keyword

nonn

Author

R. H. Hardin, Mar 10 2018

Status

approved