A303632 Number of nX4 0..1 arrays with every element unequal to 2 or 3 horizontally or vertically adjacent elements, with upper left element zero.

0, 2, 1, 4, 8, 22, 47, 123, 302, 784, 1961, 5002, 12715, 32486, 82753, 211121, 538371, 1373975, 3505385, 8944576, 22822438, 58237614, 148606194, 379208575, 967645940, 2469221128, 6300909758, 16078584921, 41029120473, 104697723446, 267166736204

Offset

1,2

Comments

Column 4 of A303636.

Links

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

Formula

Empirical: a(n) = 3*a(n-1) +a(n-2) -5*a(n-3) +a(n-4) -4*a(n-5) -9*a(n-6) -a(n-7) +39*a(n-8) -5*a(n-9) -26*a(n-10) +22*a(n-11) -a(n-12) +a(n-13) -8*a(n-14) -a(n-15) +2*a(n-16)

Example

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

Crossrefs

Cf. A303636.

Sequence in context: A294061 A113820 A319479 * A133267 A145864 A306392

Adjacent sequences: A303629 A303630 A303631 * A303633 A303634 A303635

Keyword

nonn

Author

R. H. Hardin, Apr 27 2018

Status

approved