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A305035
Number of nX3 0..1 arrays with every element unequal to 0, 1, 2, 6 or 7 king-move adjacent elements, with upper left element zero.
1
4, 3, 7, 7, 13, 23, 37, 63, 109, 183, 309, 527, 893, 1511, 2565, 4351, 7373, 12503, 21205, 35951, 60957, 103367, 175269, 297183, 503917, 854455, 1448821, 2456655, 4165565, 7063207, 11976517, 20307647, 34434061, 58387095, 99002389, 167870511
OFFSET
1,1
COMMENTS
Column 3 of A305040.
LINKS
FORMULA
Empirical: a(n) = a(n-1) +2*a(n-3) for n>6
EXAMPLE
Some solutions for n=5
..0..0..0. .0..0..1. .0..0..0. .0..0..0. .0..1..1. .0..0..0. .0..0..0
..0..0..0. .0..1..0. .0..1..0. .0..0..0. .1..0..1. .0..0..0. .0..0..0
..0..0..0. .0..0..0. .0..1..0. .0..1..0. .1..1..1. .0..0..0. .0..0..0
..0..0..0. .0..0..0. .0..0..0. .0..1..0. .1..0..1. .0..1..0. .0..1..0
..0..0..0. .0..0..0. .0..0..0. .0..0..0. .1..1..0. .1..0..0. .0..0..1
CROSSREFS
Cf. A305040.
Sequence in context: A168200 A112887 A351684 * A352832 A010654 A244335
KEYWORD
nonn
AUTHOR
R. H. Hardin, May 24 2018
STATUS
approved