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A303684 Number of nX2 0..1 arrays with every element unequal to 2, 3 or 4 king-move adjacent elements, with upper left element zero. 12
0, 3, 5, 18, 61, 209, 702, 2381, 8069, 27330, 92581, 313641, 1062502, 3599373, 12193421, 41307034, 139933701, 474046225, 1605902110, 5440232205, 18429595637, 62432996082, 211501059173, 716491292025, 2427220807318, 8222571457613 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,2
COMMENTS
Column 2 of A303690.
LINKS
FORMULA
Empirical: a(n) = 3*a(n-1) +a(n-2) +2*a(n-3) -2*a(n-4) -4*a(n-5) for n>6
EXAMPLE
Some solutions for n=5
..0..1. .0..0. .0..0. .0..1. .0..1. .0..1. .0..0. .0..1. .0..1. .0..1
..0..1. .1..1. .1..1. .0..1. .1..0. .1..0. .1..1. .0..1. .1..0. .0..1
..0..0. .0..0. .1..0. .0..0. .0..1. .0..0. .0..1. .0..0. .1..0. .1..0
..1..0. .0..0. .0..0. .1..0. .0..1. .0..1. .0..1. .0..1. .1..1. .0..1
..0..1. .1..1. .1..1. .1..0. .0..1. .1..0. .1..0. .0..1. .0..0. .0..1
CROSSREFS
Cf. A303690.
Sequence in context: A123793 A196420 A199676 * A022489 A176749 A145774
KEYWORD
nonn
AUTHOR
R. H. Hardin, Apr 28 2018
STATUS
approved

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Last modified July 17 12:04 EDT 2024. Contains 374377 sequences. (Running on oeis4.)