A302146 Number of nX3 0..1 arrays with every element equal to 0, 2, 3 or 4 horizontally or antidiagonally adjacent elements, with upper left element zero.

1, 2, 4, 10, 28, 84, 260, 816, 2576, 8152, 25824, 81840, 259408, 822304, 2606720, 8263456, 26195776, 83042752, 263252544, 834533120, 2645541888, 8386596224, 26586234880, 84280663296, 267176990976, 846974167552, 2684981361664

Offset

1,2

Comments

Column 3 of A302150.

Links

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

Formula

Empirical: a(n) = 4*a(n-1) -2*a(n-2) -2*a(n-3)

Example

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

Crossrefs

Cf. A302150.

Sequence in context: A192653 A149824 A331938 * A202135 A068875 A262543

Adjacent sequences: A302143 A302144 A302145 * A302147 A302148 A302149

Keyword

nonn

Author

R. H. Hardin, Apr 02 2018

Status

approved