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A303685
Number of nX3 0..1 arrays with every element unequal to 2, 3 or 4 king-move adjacent elements, with upper left element zero.
1
0, 5, 2, 20, 27, 108, 191, 599, 1261, 3503, 8019, 20956, 49932, 126833, 308197, 772321, 1894368, 4716189, 11620491, 28839210, 71214717, 176468284, 436228102, 1080165740, 2671530008, 6612751510, 16359100711, 40486188269, 100169626090
OFFSET
1,2
COMMENTS
Column 3 of A303690.
LINKS
FORMULA
Empirical: a(n) = a(n-1) +6*a(n-2) -3*a(n-3) -9*a(n-4) +7*a(n-5) +3*a(n-6) -20*a(n-7) -3*a(n-8) +12*a(n-9) -12*a(n-11) -3*a(n-12) +2*a(n-13) -5*a(n-14) +a(n-15) +2*a(n-16) for n>18
EXAMPLE
Some solutions for n=5
..0..1..0. .0..1..0. .0..1..1. .0..1..0. .0..1..0. .0..0..1. .0..1..0
..1..0..1. .1..1..1. .1..0..0. .1..0..1. .1..1..1. .1..1..0. .1..0..1
..1..0..0. .0..1..0. .0..0..1. .0..1..0. .0..1..0. .0..1..1. .0..0..1
..0..0..1. .0..0..1. .1..0..1. .1..1..1. .1..0..0. .0..1..0. .1..0..0
..1..0..1. .1..1..0. .0..1..0. .0..1..0. .1..0..1. .1..0..1. .1..0..1
CROSSREFS
Cf. A303690.
Sequence in context: A327316 A206582 A276533 * A189746 A191667 A130329
KEYWORD
nonn
AUTHOR
R. H. Hardin, Apr 28 2018
STATUS
approved