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A318045
T(n,k)=Number of nXk 0..1 arrays with every element unequal to 0, 2, 3 or 4 horizontally, vertically or antidiagonally adjacent elements, with upper left element zero.
8
1, 1, 1, 1, 2, 1, 1, 2, 2, 1, 1, 3, 8, 3, 1, 1, 6, 21, 21, 6, 1, 1, 17, 86, 140, 86, 17, 1, 1, 46, 377, 905, 905, 377, 46, 1, 1, 124, 1648, 6179, 10563, 6179, 1648, 124, 1, 1, 341, 7261, 42793, 116212, 116212, 42793, 7261, 341, 1, 1, 947, 31969, 297043, 1304057, 2098813
OFFSET
1,5
COMMENTS
Table starts
.1...1.....1.......1.........1...........1............1..............1
.1...2.....2.......3.........6..........17...........46............124
.1...2.....8......21........86.........377.........1648...........7261
.1...3....21.....140.......905........6179........42793.........297043
.1...6....86.....905.....10563......116212......1304057.......14683085
.1..17...377....6179....116212.....2098813.....37826270......685931021
.1..46..1648...42793...1304057....37826270...1097286743....32035215365
.1.124..7261..297043..14683085...685931021..32035215365..1507709268026
.1.341.31969.2056698.165135266.12431437346.933917327711.70833352314014
LINKS
FORMULA
Empirical for column k:
k=1: a(n) = a(n-1)
k=2: a(n) = 3*a(n-1) -a(n-2) +a(n-3) +a(n-4) -2*a(n-5) -a(n-6) for n>7
k=3: [order 21] for n>23
k=4: [order 72] for n>74
EXAMPLE
Some solutions for n=5 k=4
..0..1..0..1. .0..1..0..1. .0..0..1..0. .0..0..1..1. .0..1..0..1
..1..0..1..0. .1..1..1..0. .0..1..0..1. .0..1..0..0. .1..1..0..0
..0..1..1..0. .0..1..0..1. .1..0..1..0. .1..0..0..1. .0..0..1..1
..0..1..0..1. .1..0..0..1. .0..1..1..0. .1..1..0..0. .1..1..0..0
..1..0..1..0. .1..0..1..0. .1..0..0..1. .0..1..0..1. .0..1..0..1
CROSSREFS
Sequence in context: A241926 A174446 A071201 * A240656 A106476 A101566
KEYWORD
nonn,tabl
AUTHOR
R. H. Hardin, Aug 13 2018
STATUS
approved