

A197049


Number of nX3 0..4 arrays with each element equal to the number its horizontal and vertical zero neighbors


4



2, 4, 10, 18, 38, 78, 156, 320, 654, 1326, 2706, 5518, 11228, 22884, 46634, 94978, 193518, 394286, 803220, 1636448, 3334030, 6792334, 13838202, 28192958, 57437684, 117018884, 238404906, 485705682, 989536598, 2016000430, 4107230284
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OFFSET

1,1


COMMENTS

Every 0 is next to 0 0's, every 1 is next to 1 0's, every 2 is next to 2 0's, every 3 is next to 3 0's, every 4 is next to 4 0's
Column 3 of A197054


LINKS

R. H. Hardin, Table of n, a(n) for n = 1..200


FORMULA

Empirical: a(n) = a(n1) +a(n2) +3*a(n3) a(n4) a(n5) for n>6
Equivalent empirical g.f. 2*x 2*x^2*(1+x)*(2*x^3x^2x2) / ( 1xx^23*x^3+x^4+x^5 ).  R. J. Mathar, Oct 10 2011


EXAMPLE

Some solutions for n=5
..2..0..2....0..1..1....2..0..1....0..3..0....0..3..0....0..3..0....0..2..0
..0..4..0....1..2..0....0..2..1....3..0..2....2..0..2....2..0..3....1..1..1
..2..0..3....2..0..3....2..1..0....0..2..1....1..1..1....1..2..0....1..0..2
..1..2..0....0..4..0....0..2..1....1..2..0....0..3..0....0..2..1....1..2..0
..0..1..1....2..0..2....2..0..1....1..0..2....2..0..2....2..0..1....0..1..1


CROSSREFS

Sequence in context: A189892 A240877 A218008 * A104723 A206140 A079162
Adjacent sequences: A197046 A197047 A197048 * A197050 A197051 A197052


KEYWORD

nonn


AUTHOR

R. H. Hardin Oct 09 2011


STATUS

approved



