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A303963 Number of nX2 0..1 arrays with every element unequal to 0, 1, 3 or 5 king-move adjacent elements, with upper left element zero. 8
2, 5, 9, 21, 53, 105, 237, 577, 1205, 2681, 6349, 13681, 30309, 70377, 154429, 342177, 783957, 1737881, 3857581, 8760529, 19527749, 43436873, 98090781, 219270657, 488654645, 1099633401, 2461435533, 5493590065, 12336038693, 27628989353 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
COMMENTS
Column 2 of A303969.
LINKS
FORMULA
Empirical: a(n) = a(n-1) +8*a(n-3) -4*a(n-4)
EXAMPLE
Some solutions for n=5
..0..1. .0..1. .0..1. .0..0. .0..0. .0..1. .0..1. .0..0. .0..0. .0..0
..0..0. .1..1. .1..1. .0..1. .0..0. .0..0. .1..1. .0..0. .0..1. .1..0
..0..0. .1..1. .1..1. .1..1. .0..1. .0..0. .0..0. .0..0. .0..0. .1..1
..0..0. .1..0. .1..1. .1..1. .1..1. .0..0. .1..0. .1..0. .0..0. .1..1
..1..0. .0..0. .0..1. .0..1. .1..1. .0..1. .1..1. .1..1. .0..1. .1..0
CROSSREFS
Cf. A303969.
Sequence in context: A155042 A001851 A356375 * A304349 A024822 A218966
KEYWORD
nonn
AUTHOR
R. H. Hardin, May 03 2018
STATUS
approved

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Last modified April 21 00:22 EDT 2024. Contains 371850 sequences. (Running on oeis4.)