A222741 Number of nX2 0..3 arrays with exactly floor(nX2/2) elements equal to at least one horizontal or antidiagonal neighbor, with new values introduced in row major 0..3 order

0, 6, 20, 685, 5370, 123410, 1341616, 25106526, 321557310, 5447475968, 76079350800, 1228204709225, 17971182592538, 283558808435910, 4256630623481552, 66474347415079345, 1012439882213494794

Offset

1,2

Comments

Column 2 of A222747

Links

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

Example

Some solutions for n=3
..0..1....0..1....0..1....0..1....0..1....0..1....0..1....0..0....0..1....0..1
..2..0....0..0....1..1....2..2....1..1....1..1....0..1....0..1....1..1....0..0
..0..0....0..2....2..0....2..1....0..1....2..3....1..1....0..1....0..2....0..1

Crossrefs

Sequence in context: A280039 A216912 A175671 * A338427 A069257 A133885

Adjacent sequences: A222738 A222739 A222740 * A222742 A222743 A222744

Keyword

nonn

Author

R. H. Hardin Mar 04 2013

Status

approved