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A301947
Number of nX4 0..1 arrays with every element equal to 1, 2 or 3 horizontally or antidiagonally adjacent elements, with upper left element zero.
1
2, 16, 123, 947, 7326, 56710, 439078, 3399722, 26323903, 203825456, 1578217598, 12220118582, 94620225492, 732643232114, 5672847473255, 43924787764759, 340109088005893, 2633460459021237, 20390851741033347, 157886112662767667
OFFSET
1,1
COMMENTS
Column 4 of A301951.
LINKS
FORMULA
Empirical: a(n) = 9*a(n-1) -8*a(n-2) -14*a(n-3) +4*a(n-4) +4*a(n-5) -a(n-6)
EXAMPLE
Some solutions for n=5
..0..0..1..0. .0..0..1..1. .0..0..1..1. .0..0..0..0. .0..0..0..0
..0..1..0..1. .0..0..1..1. .1..1..0..1. .0..0..1..1. .0..1..0..1
..0..0..1..1. .0..0..0..1. .1..0..1..1. .0..1..1..1. .1..0..1..1
..0..1..0..0. .1..1..1..0. .0..0..0..1. .1..0..1..0. .0..0..1..0
..0..0..0..0. .1..1..0..0. .1..1..1..1. .0..1..0..0. .0..0..0..0
CROSSREFS
Cf. A301951.
Sequence in context: A209361 A341925 A229808 * A027309 A241466 A069868
KEYWORD
nonn
AUTHOR
R. H. Hardin, Mar 29 2018
STATUS
approved