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A303619
Number of nX3 0..1 arrays with every element equal to 0, 2, 3, 4, 5 or 6 horizontally, diagonally or antidiagonally adjacent elements, with upper left element zero.
1
1, 12, 38, 148, 616, 2520, 10288, 42100, 172268, 704776, 2883500, 11797636, 48268920, 197487780, 808003420, 3305872824, 13525678764, 55339088836, 226414867352, 926355911364, 3790101263196, 15506855855704, 63444895485516
OFFSET
1,2
COMMENTS
Column 3 of A303624.
LINKS
FORMULA
Empirical: a(n) = 5*a(n-1) -5*a(n-2) +8*a(n-3) -12*a(n-4) +4*a(n-5) -4*a(n-6) for n>8
EXAMPLE
Some solutions for n=5
..0..1..1. .0..1..0. .0..0..1. .0..1..1. .0..0..0. .0..0..0. .0..0..0
..1..1..1. .1..1..1. .0..0..1. .0..1..1. .0..0..0. .0..0..0. .0..0..1
..0..1..0. .0..1..1. .1..0..0. .1..1..1. .0..0..1. .1..0..0. .0..0..1
..0..1..1. .1..1..1. .0..0..0. .1..1..0. .1..0..0. .0..0..0. .1..0..0
..1..1..0. .1..1..1. .0..0..1. .1..1..1. .0..0..1. .1..0..1. .0..0..0
CROSSREFS
Cf. A303624.
Sequence in context: A212510 A213490 A259517 * A167712 A209872 A186779
KEYWORD
nonn
AUTHOR
R. H. Hardin, Apr 27 2018
STATUS
approved