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A281062
Number of 7Xn 0..1 arrays with no element equal to more than one of its horizontal and antidiagonal neighbors, with the exception of exactly two elements, and with new values introduced in order 0 sequentially upwards.
1
0, 1686, 15028, 27635, 58005, 119205, 221212, 394884, 689397, 1191475, 2050466, 3523654, 6051629, 10389370, 17827528, 30568529, 52364160, 89595493, 153099429, 261254732, 445190263, 757565887, 1287362382, 2184769552, 3703030677
OFFSET
1,2
COMMENTS
Row 7 of A281056.
LINKS
FORMULA
Empirical: a(n) = 6*a(n-1) -12*a(n-2) +5*a(n-3) +12*a(n-4) -12*a(n-5) -3*a(n-6) +6*a(n-7) -a(n-9) for n>20
EXAMPLE
Some solutions for n=4
..0..1..1..0. .0..1..1..0. .0..1..0..1. .0..0..0..1. .0..1..0..1
..0..0..1..0. .1..0..1..0. .0..1..1..0. .1..1..0..1. .0..1..0..1
..1..1..0..1. .1..0..1..0. .0..1..0..1. .0..1..0..1. .0..1..0..0
..0..1..0..1. .0..1..0..1. .0..1..0..0. .0..1..0..1. .0..1..1..0
..1..0..1..0. .0..1..0..1. .1..0..1..1. .0..1..0..0. .0..0..1..0
..1..0..1..0. .1..0..0..1. .1..0..0..1. .1..0..1..1. .1..0..1..0
..0..0..1..0. .0..1..0..1. .1..1..0..1. .1..0..0..1. .1..1..0..0
CROSSREFS
Cf. A281056.
Sequence in context: A205515 A335338 A263061 * A020241 A065903 A204488
KEYWORD
nonn
AUTHOR
R. H. Hardin, Jan 13 2017
STATUS
approved