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A303520
Number of nX3 0..1 arrays with every element equal to 0, 1, 3, 4, 5 or 6 horizontally, diagonally or antidiagonally adjacent elements, with upper left element zero.
1
3, 11, 18, 39, 95, 246, 687, 2023, 6126, 19571, 63599, 209618, 700539, 2356511, 7961506, 26985119, 91629471, 311488830, 1059693975, 3606749879, 12279357318, 41813315995, 142397488591, 484976347386, 1651802107971, 5626099528751
OFFSET
1,1
COMMENTS
Column 3 of A303525.
LINKS
FORMULA
Empirical: a(n) = 4*a(n-1) -3*a(n-2) +10*a(n-3) -22*a(n-4) +6*a(n-5) -31*a(n-6) +10*a(n-7) -3*a(n-8) -14*a(n-9) -8*a(n-10) -32*a(n-11) -16*a(n-12) for n>15
EXAMPLE
Some solutions for n=5
..0..0..0. .0..1..1. .0..1..0. .0..1..0. .0..1..0. .0..0..1. .0..1..0
..0..1..0. .0..0..0. .1..1..0. .0..1..1. .0..1..1. .1..1..1. .0..0..0
..0..1..1. .0..1..0. .0..1..0. .0..1..0. .0..1..0. .1..0..1. .0..1..0
..0..1..0. .0..1..0. .0..1..0. .0..1..0. .0..0..0. .1..0..1. .0..1..0
..0..0..0. .0..0..0. .1..0..0. .0..0..0. .0..1..0. .0..1..1. .0..0..0
CROSSREFS
Cf. A303525.
Sequence in context: A316839 A308047 A119141 * A225144 A335135 A228470
KEYWORD
nonn
AUTHOR
R. H. Hardin, Apr 25 2018
STATUS
approved