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A301791
Number of 2Xn 0..1 arrays with every element equal to 0 or 1 horizontally or antidiagonally adjacent elements, with upper left element zero.
2
2, 5, 6, 9, 14, 22, 35, 56, 90, 145, 234, 378, 611, 988, 1598, 2585, 4182, 6766, 10947, 17712, 28658, 46369, 75026, 121394, 196419, 317812, 514230, 832041, 1346270, 2178310, 3524579, 5702888, 9227466, 14930353, 24157818, 39088170, 63245987
OFFSET
1,1
COMMENTS
Row 2 of A301790.
LINKS
FORMULA
Empirical: a(n) = 2*a(n-1) -a(n-3) for n>5.
EXAMPLE
Some solutions for n=5
..0..0..1..0..0. .0..1..0..0..1. .0..1..0..1..1. .0..1..0..0..1
..1..0..1..1..0. .0..1..1..0..0. .0..1..0..0..1. .0..1..1..0..1
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Mar 26 2018
STATUS
approved