A304143 Number of nX2 0..1 arrays with every element unequal to 1, 2, 3 or 6 king-move adjacent elements, with upper left element zero.

1, 7, 14, 33, 70, 157, 346, 769, 1710, 3813, 8514, 19049, 42678, 95757, 215114, 483793, 1089150, 2454197, 5534546, 12490169, 28205510, 63730653, 144073434, 325848609, 737262478, 1668717957, 3778162914, 8556569353, 19383222230, 43918469037

Offset

1,2

Comments

Column 2 of A304149.

Links

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

Formula

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

Empirical g.f: x -x^2*(-7+16*x^2+24*x^3+12*x^4) / ( (2*x-1) *(1+x) *(2*x^3+2*x^2+x-1) ). - R. J. Mathar, May 08 2018

Example

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

Crossrefs

Cf. A304149.

Sequence in context: A293359 A134384 A352851 * A055780 A161814 A333594

Adjacent sequences: A304140 A304141 A304142 * A304144 A304145 A304146

Keyword

nonn

Author

R. H. Hardin, May 07 2018

Status

approved