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A302630
Number of nX3 0..1 arrays with every element equal to 0, 1, 3 or 6 horizontally, diagonally or antidiagonally adjacent elements, with upper left element zero.
1
3, 9, 8, 19, 42, 82, 189, 469, 1029, 2372, 5661, 12788, 29440, 69193, 158299, 364581, 849888, 1955567, 4508226, 10463966, 24138613, 55695301, 128985441, 297870624, 687700145, 1590857932, 3675434388, 8488858425, 19626303139, 45350971169
OFFSET
1,1
COMMENTS
Column 3 of A302635.
LINKS
FORMULA
Empirical: a(n) = a(n-1) +9*a(n-3) -4*a(n-4) +2*a(n-5) -10*a(n-6) +4*a(n-7) +4*a(n-9) for n>13
EXAMPLE
Some solutions for n=5
..0..1..0. .0..1..0. .0..1..0. .0..1..0. .0..1..0. .0..1..0. .0..0..1
..0..1..1. .0..1..0. .0..1..0. .0..0..0. .0..1..0. .0..1..1. .0..1..0
..0..1..0. .0..1..0. .0..1..0. .0..1..0. .0..1..0. .0..1..0. .1..1..1
..0..1..0. .0..1..0. .0..1..0. .0..1..0. .0..1..1. .0..1..0. .1..1..0
..1..0..0. .0..0..1. .0..1..0. .1..0..0. .0..1..0. .0..0..1. .0..1..0
CROSSREFS
Cf. A302635.
Sequence in context: A231863 A179589 A368737 * A128686 A161574 A103555
KEYWORD
nonn
AUTHOR
R. H. Hardin, Apr 10 2018
STATUS
approved