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A301609
Number of n X n 0..1 arrays with every element equal to 1, 2 or 3 horizontally or vertically adjacent elements, with upper left element zero.
0
0, 3, 62, 3816, 758338, 488491106, 1019565752074, 6897694015722898, 151249886315100454600, 10749578188598491367494716
OFFSET
1,2
COMMENTS
Diagonal of A301615.
EXAMPLE
Some solutions for n=5
..0..0..0..0..0. .0..0..0..0..0. .0..0..0..0..0. .0..0..0..0..0
..0..0..0..1..1. .0..0..1..0..1. .1..1..1..1..1. .1..1..1..1..1
..0..1..1..1..1. .1..1..1..0..1. .1..1..0..0..1. .0..0..1..0..0
..0..0..0..0..1. .0..0..0..1..0. .1..0..0..1..1. .0..0..1..0..0
..1..1..0..1..1. .1..1..0..1..0. .0..0..0..1..1. .0..0..1..0..0
CROSSREFS
Cf. A301615.
Sequence in context: A275746 A177496 A104403 * A144422 A327053 A135444
KEYWORD
nonn
AUTHOR
R. H. Hardin, Mar 24 2018
STATUS
approved