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A304257
Number of nX2 0..1 arrays with every element unequal to 2, 3, 5 or 7 king-move adjacent elements, with upper left element zero.
3
0, 3, 4, 9, 18, 33, 72, 133, 278, 541, 1084, 2169, 4290, 8617, 17088, 34189, 68110, 135893, 271300, 541057, 1080538, 2156129, 4305416, 8595925, 17164582, 34280653, 68463372, 136756489, 273176690, 545743769, 1090334032, 2178507165, 4353007166
OFFSET
1,2
COMMENTS
Column 2 of A304263.
LINKS
FORMULA
Empirical: a(n) = 2*a(n-1) +3*a(n-2) -4*a(n-3) -6*a(n-4) +4*a(n-5) for n>6
EXAMPLE
Some solutions for n=5
..0..1. .0..1. .0..1. .0..1. .0..0. .0..1. .0..1. .0..1. .0..1. .0..1
..1..0. .1..0. .0..1. .1..0. .1..1. .1..0. .1..0. .0..1. .1..0. .0..1
..0..1. .1..0. .1..0. .1..0. .0..1. .0..1. .1..0. .0..1. .1..0. .0..1
..0..1. .0..1. .1..0. .1..0. .0..0. .1..0. .1..0. .1..0. .0..1. .0..1
..1..0. .0..1. .1..0. .1..0. .1..1. .1..0. .0..1. .0..1. .1..0. .1..0
CROSSREFS
Cf. A304263.
Sequence in context: A192115 A103295 A352134 * A217492 A374965 A178784
KEYWORD
nonn
AUTHOR
R. H. Hardin, May 09 2018
STATUS
approved