A300500 Number of nX2 0..1 arrays with every element equal to 0, 1, 3 or 4 horizontally, vertically or antidiagonally adjacent elements, with upper left element zero.

2, 3, 2, 3, 6, 6, 11, 26, 43, 82, 178, 347, 682, 1403, 2822, 5638, 11411, 23026, 46291, 93346, 188258, 379187, 764178, 1540467, 3104262, 6255878, 12608667, 25410698, 51210491, 103208946, 208003346, 419198091, 844835898, 1702649067, 3431439878

Offset

1,1

Comments

Column 2 of A300506.

Links

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

Formula

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

Example

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

Crossrefs

Cf. A300506.

Sequence in context: A085212 A079025 A165930 * A339132 A064895 A120877

Adjacent sequences: A300497 A300498 A300499 * A300501 A300502 A300503

Keyword

nonn

Author

R. H. Hardin, Mar 07 2018

Status

approved