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A301663
Number of n X n 0..1 arrays with every element equal to 1, 2 or 4 horizontally or vertically adjacent elements, with upper left element zero.
0
0, 3, 30, 564, 21224, 1537496, 225780260, 68862687289, 42474080549252, 53316494203981492
OFFSET
1,2
COMMENTS
Diagonal of A301669.
EXAMPLE
Some solutions for n=5
..0..1..1..0..0. .0..0..1..1..0. .0..0..1..0..1. .0..0..1..1..1
..0..1..0..1..1. .1..1..0..0..0. .1..0..1..0..1. .0..1..0..0..1
..1..1..0..1..0. .1..1..1..1..1. .1..1..1..0..1. .1..1..0..1..1
..1..0..1..0..0. .0..1..0..0..1. .0..0..0..1..1. .0..0..0..0..0
..0..0..1..1..1. .0..0..0..1..1. .0..1..1..0..0. .1..1..0..1..1
CROSSREFS
Cf. A301669.
Sequence in context: A370057 A300617 A365653 * A319940 A177449 A184900
KEYWORD
nonn
AUTHOR
R. H. Hardin, Mar 25 2018
STATUS
approved