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A301825
Number of 4Xn 0..1 arrays with every element equal to 1 or 2 horizontally or antidiagonally adjacent elements, with upper left element zero.
1
0, 13, 8, 68, 299, 1351, 6653, 30441, 146175, 682879, 3234177, 15226483, 71859897, 338825989, 1598126524, 7536923120, 35546600366, 167645751951, 790663538862, 3728968861295, 17586797354805, 82943890400479, 391184964947659
OFFSET
1,2
COMMENTS
Row 4 of A301823.
FORMULA
Empirical recurrence of order 66 (see link above)
EXAMPLE
Some solutions for n=5
..0..0..0..1..1. .0..0..0..1..1. .0..0..1..1..1. .0..0..0..0..0
..1..1..0..1..0. .1..1..1..0..0. .1..1..0..0..0. .1..1..1..1..0
..1..0..1..0..1. .0..0..1..1..0. .0..0..1..1..1. .0..0..1..0..0
..0..1..0..1..1. .0..0..1..0..0. .1..1..0..0..0. .0..0..1..1..1
CROSSREFS
Cf. A301823.
Sequence in context: A166522 A206610 A250031 * A300377 A300679 A377610
KEYWORD
nonn
AUTHOR
R. H. Hardin, Mar 27 2018
STATUS
approved