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A297735
Number of 3Xn 0..1 arrays with every 1 horizontally, diagonally or antidiagonally adjacent to 2 or 4 neighboring 1s.
1
1, 3, 17, 34, 92, 223, 700, 1747, 4931, 12767, 35978, 94910, 262007, 698588, 1916541, 5144619, 14035991, 37816996, 102894248, 277866327, 754687018, 2040711739, 5537019209, 14984261865, 40631762944, 110008357730, 298195807995
OFFSET
1,2
COMMENTS
Row 3 of A297733.
LINKS
FORMULA
Empirical: a(n) = 2*a(n-1) +4*a(n-2) -6*a(n-3) +7*a(n-4) -12*a(n-5) -19*a(n-6) +16*a(n-7) +10*a(n-8) +4*a(n-9)
EXAMPLE
Some solutions for n=7
..1..1..0..0..0..0..0. .0..0..1..1..1..1..1. .0..0..0..1..1..1..1
..0..1..1..0..1..1..0. .0..0..1..1..1..1..1. .1..1..0..1..1..1..1
..0..0..0..0..1..1..0. .0..0..0..0..0..0..0. .1..1..0..0..0..0..0
CROSSREFS
Cf. A297733.
Sequence in context: A115355 A146021 A146133 * A266062 A031290 A152908
KEYWORD
nonn
AUTHOR
R. H. Hardin, Jan 04 2018
STATUS
approved