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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
1
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
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
KEYWORD
nonn
AUTHOR
R. H. Hardin Mar 04 2013
STATUS
approved