A300346 Number of nX4 0..1 arrays with every element equal to 1 or 2 horizontally, vertically or antidiagonally adjacent elements, with upper left element zero.

2, 15, 26, 58, 152, 325, 729, 1609, 3577, 7931, 17605, 39106, 86859, 192976, 428779, 952794, 2117289, 4705103, 10455942, 23235911, 51636607, 114750985, 255009010, 566702101, 1259372546, 2798682776, 6219466851, 13821419716, 30715116147

Offset

1,1

Comments

Column 4 of A300350.

Links

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

Formula

Empirical: a(n) = 5*a(n-1) -8*a(n-2) +4*a(n-3) +a(n-5) -3*a(n-6) +4*a(n-7) -2*a(n-8) +a(n-9) -a(n-10) -a(n-12) +a(n-13) for n>16

Example

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

Crossrefs

Cf. A300350.

Sequence in context: A023651 A116028 A175828 * A370031 A338457 A153080

Adjacent sequences: A300343 A300344 A300345 * A300347 A300348 A300349

Keyword

nonn

Author

R. H. Hardin, Mar 03 2018

Status

approved