A320359 Number of nX3 0..1 arrays with every element unequal to 2, 3, 4 or 6 horizontally, vertically or antidiagonally adjacent elements, with upper left element zero.

0, 1, 4, 13, 60, 258, 1111, 4836, 21007, 91214, 396170, 1720608, 7472694, 32454615, 140953263, 612172021, 2658715999, 11547033504, 50149763813, 217804756979, 945944877379, 4108320326435, 17842790116095, 77492779006291

Offset

1,3

Comments

Column 3 of A320364.

Links

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

Formula

Empirical: a(n) = 5*a(n-1) -4*a(n-2) +9*a(n-3) -19*a(n-4) +12*a(n-5) -24*a(n-6) +5*a(n-7) -9*a(n-8) +28*a(n-9) +20*a(n-10) -13*a(n-11) -31*a(n-12) -8*a(n-13) +14*a(n-14) +19*a(n-15) +4*a(n-16) -a(n-17) -2*a(n-18) for n>20

Example

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

Crossrefs

Cf. A320364.

Sequence in context: A219367 A149487 A372125 * A057712 A208592 A367888

Adjacent sequences: A320356 A320357 A320358 * A320360 A320361 A320362

Keyword

nonn

Author

R. H. Hardin, Oct 11 2018

Status

approved