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A298714
Number of nX3 0..1 arrays with every element equal to 2, 3, 4, 6 or 7 king-move adjacent elements, with upper left element zero.
1
0, 2, 4, 13, 63, 264, 1005, 4113, 16720, 67541, 273173, 1105028, 4470455, 18086203, 73164414, 295979201, 1197372779, 4843899390, 19595676337, 79273069299, 320694228442, 1297348415225, 5248341466951, 21231835277428, 85892055453779
OFFSET
1,2
COMMENTS
Column 3 of A298719.
LINKS
FORMULA
Empirical: a(n) = 3*a(n-1) +4*a(n-2) +3*a(n-3) -2*a(n-4) -18*a(n-5) -29*a(n-6) -32*a(n-7) +74*a(n-8) +74*a(n-9) -90*a(n-10) -73*a(n-11) +33*a(n-12) -21*a(n-13) -29*a(n-14) +32*a(n-15) +4*a(n-16) +4*a(n-17) +8*a(n-18)
EXAMPLE
Some solutions for n=7
..0..0..1. .0..0..1. .0..1..1. .0..0..0. .0..0..0. .0..0..0. .0..0..0
..0..1..1. .0..1..1. .0..0..1. .1..0..0. .0..1..0. .1..0..1. .1..0..1
..0..0..0. .0..0..0. .1..1..1. .1..1..1. .1..1..1. .1..1..1. .1..1..1
..0..0..0. .0..0..0. .1..1..1. .1..1..1. .1..1..1. .1..1..1. .1..1..1
..0..1..0. .0..1..0. .1..0..1. .1..0..1. .1..0..1. .1..0..0. .0..0..1
..1..0..1. .1..1..0. .1..0..0. .1..0..0. .1..0..0. .0..0..1. .0..1..1
..1..1..1. .1..0..0. .1..1..0. .1..1..0. .1..1..0. .0..1..1. .0..0..1
CROSSREFS
Cf. A298719.
Sequence in context: A298128 A132786 A298065 * A306445 A216670 A103845
KEYWORD
nonn
AUTHOR
R. H. Hardin, Jan 25 2018
STATUS
approved