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A283727
Number of 2 X n 0..1 arrays with no 1 equal to more than two of its horizontal, diagonal and antidiagonal neighbors, with the exception of exactly one element.
1
0, 0, 10, 60, 242, 1032, 4220, 16376, 62564, 235728, 875630, 3220084, 11746262, 42545240, 153181664, 548710320, 1956760904, 6950669984, 24604072658, 86824376236, 305540509370, 1072522794920, 3756266150212, 13128230615656
OFFSET
1,3
LINKS
FORMULA
Empirical: a(n) = 6*a(n-1) - 7*a(n-2) - 31*a(n-4) + 14*a(n-5) + 51*a(n-6) + 52*a(n-7) + 12*a(n-8) - 96*a(n-9) - 64*a(n-10).
Empirical g.f.: 2*x^3*(1 - 2*x)*(1 + 2*x)*(5 - 4*x^2) / ((1 + x + 2*x^2)^2*(1 - 4*x + x^2 + 4*x^3)^2). - Colin Barker, Feb 21 2019
EXAMPLE
Some solutions for n=4:
..0..1..1..1. .1..1..0..1. .0..1..0..0. .0..1..1..0. .1..1..1..1
..0..0..0..1. .0..1..1..1. .1..1..1..1. .0..1..0..1. .0..1..0..1
CROSSREFS
Row 2 of A283726.
Sequence in context: A144560 A076160 A266732 * A349415 A228581 A241929
KEYWORD
nonn
AUTHOR
R. H. Hardin, Mar 15 2017
STATUS
approved