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A296985
Number of nX3 0..1 arrays with each 1 adjacent to 3, 4 or 5 king-move neighboring 1s.
1
1, 4, 14, 28, 98, 447, 1653, 6507, 27374, 111866, 455776, 1879650, 7732294, 31739780, 130516126, 536728543, 2206092839, 9069307066, 37287485232, 153290332616, 630187059733, 2590803232685, 10651107068004, 43787867995065
OFFSET
1,2
COMMENTS
Column 3 of A296990.
LINKS
FORMULA
Empirical: a(n) = 3*a(n-1) +2*a(n-2) +19*a(n-3) -19*a(n-4) -52*a(n-5) -67*a(n-6) +15*a(n-7) +155*a(n-8) +207*a(n-9) -104*a(n-10) -157*a(n-11) -172*a(n-12) +53*a(n-13) +63*a(n-14) +38*a(n-15) +14*a(n-16) +19*a(n-17) +3*a(n-18) +4*a(n-19) +2*a(n-20)
EXAMPLE
Some solutions for n=7
..0..1..1. .1..1..0. .0..0..0. .0..1..0. .0..0..0. .0..0..0. .0..1..0
..0..1..1. .1..1..1. .0..1..1. .1..1..1. .0..0..0. .0..0..0. .1..1..1
..1..1..0. .0..0..1. .1..1..1. .0..1..1. .1..1..0. .1..1..0. .0..1..0
..1..0..0. .0..1..1. .0..1..0. .0..0..0. .1..1..0. .1..1..0. .0..1..0
..1..1..0. .0..1..1. .0..1..1. .0..1..1. .0..0..0. .0..0..0. .0..1..1
..1..1..0. .0..1..1. .1..1..0. .0..1..1. .0..1..1. .1..1..0. .1..1..0
..1..1..0. .0..1..1. .1..1..0. .0..1..1. .0..1..1. .1..1..0. .1..1..0
CROSSREFS
Cf. A296990.
Sequence in context: A289179 A033690 A316213 * A338311 A244714 A218212
KEYWORD
nonn
AUTHOR
R. H. Hardin, Dec 22 2017
STATUS
approved