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A318217
Number of nX3 0..1 arrays with every element unequal to 2, 3, 4 or 5 horizontally, vertically or antidiagonally adjacent elements, with upper left element zero.
1
0, 1, 4, 18, 86, 413, 1975, 9474, 45415, 217714, 1043722, 5003565, 23986950, 114992767, 551272103, 2642783040, 12669427963, 60736883262, 291170919400, 1395865242913, 6691738929130, 32080009243747, 153790666966961
OFFSET
1,3
COMMENTS
Column 3 of A318222.
LINKS
FORMULA
Empirical: a(n) = 5*a(n-1) -a(n-2) +a(n-3) -5*a(n-4) +3*a(n-5) -3*a(n-6) +a(n-7) -8*a(n-8) -4*a(n-10) +2*a(n-11)
EXAMPLE
Some solutions for n=5
..0..1..0. .0..1..0. .0..1..0. .0..1..1. .0..1..1. .0..1..0. .0..1..1
..1..1..0. .1..1..1. .1..0..1. .1..0..0. .1..0..0. .1..0..1. .1..0..0
..0..1..1. .0..0..0. .1..0..0. .1..0..1. .0..1..1. .1..1..0. .0..0..1
..0..0..1. .1..1..1. .1..1..1. .0..0..0. .1..1..0. .0..0..1. .1..0..1
..1..1..0. .0..1..0. .0..1..0. .1..0..1. .0..0..1. .1..1..0. .0..1..0
CROSSREFS
Cf. A318222.
Sequence in context: A055834 A079567 A030278 * A341248 A151252 A084847
KEYWORD
nonn
AUTHOR
R. H. Hardin, Aug 21 2018
STATUS
approved