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A301820
Number of nX5 0..1 arrays with every element equal to 1 or 2 horizontally or antidiagonally adjacent elements, with upper left element zero.
1
3, 18, 74, 299, 1197, 4785, 19130, 76499, 305959, 1223777, 4895020, 19579955, 78319649, 313278369, 1253113182, 5012452355, 20049808955, 80199235249, 320796940304, 1283187760387, 5132751040565, 20531004161105, 82124016643074
OFFSET
1,1
COMMENTS
Column 5 of A301823.
LINKS
FORMULA
Empirical: a(n) = 8*a(n-1) -22*a(n-2) +28*a(n-3) -17*a(n-4) +4*a(n-5) for n>7
EXAMPLE
Some solutions for n=5
..0..0..0..0..1. .0..0..0..1..0. .0..0..1..1..1. .0..0..1..1..1
..1..1..0..1..1. .1..1..1..0..1. .0..0..0..0..0. .0..0..0..1..0
..1..1..0..1..0. .0..0..0..1..1. .1..1..1..1..0. .1..1..1..0..0
..1..0..1..0..0. .1..1..0..1..1. .0..0..1..0..1. .0..0..1..1..0
..0..1..1..1..1. .1..0..0..1..1. .1..1..0..1..1. .0..0..1..0..0
CROSSREFS
Cf. A301823.
Sequence in context: A280804 A152897 A059393 * A094033 A245580 A043008
KEYWORD
nonn
AUTHOR
R. H. Hardin, Mar 27 2018
STATUS
approved