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A301996
Number of nX5 0..1 arrays with every element equal to 1, 2 or 4 horizontally or antidiagonally adjacent elements, with upper left element zero.
1
3, 18, 84, 468, 2856, 17800, 110036, 674984, 4130664, 25284068, 154853080, 948637896, 5811528980, 35601208264, 218086661704, 1335953081860, 8183781374680, 50132301702344, 307101237458324, 1881245567361512
OFFSET
1,1
COMMENTS
Column 5 of A301999.
LINKS
FORMULA
Empirical: a(n) = 18*a(n-1) -141*a(n-2) +661*a(n-3) -2058*a(n-4) +4393*a(n-5) -6412*a(n-6) +6060*a(n-7) -3280*a(n-8) +640*a(n-9) +192*a(n-10) -64*a(n-11) for n>12
EXAMPLE
Some solutions for n=5
..0..0..0..0..0. .0..0..1..1..0. .0..0..1..1..1. .0..0..1..0..0
..1..1..1..1..0. .1..1..1..0..1. .0..0..0..0..1. .0..1..0..0..0
..0..0..1..0..0. .1..0..1..1..1. .1..1..1..1..0. .1..1..0..1..1
..0..1..1..1..0. .0..0..1..0..1. .0..0..0..0..0. .0..0..1..0..0
..0..0..1..0..0. .0..0..0..1..1. .1..1..0..1..1. .1..1..0..1..1
CROSSREFS
Cf. A301999.
Sequence in context: A122069 A103897 A119424 * A218924 A037295 A290331
KEYWORD
nonn
AUTHOR
R. H. Hardin, Mar 30 2018
STATUS
approved