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A302619
Number of nX4 0..1 arrays with every element equal to 0, 1, 2 or 6 horizontally, diagonally or antidiagonally adjacent elements, with upper left element zero.
1
8, 37, 45, 130, 367, 917, 2533, 6871, 18334, 49596, 133871, 360493, 972318, 2622309, 7069651, 19062876, 51403186, 138601138, 373723944, 1007717328, 2717208445, 7326688182, 19755736142, 53269455264, 143635996311, 387300855495
OFFSET
1,1
COMMENTS
Column 4 of A302623.
LINKS
FORMULA
Empirical: a(n) = a(n-1) +3*a(n-2) +6*a(n-3) -a(n-4) -8*a(n-5) -7*a(n-6) +2*a(n-7) +5*a(n-8) for n>10
EXAMPLE
Some solutions for n=5
..0..0..1..0. .0..1..0..0. .0..0..1..0. .0..1..0..1. .0..1..0..1
..0..1..1..0. .0..1..0..1. .1..0..1..0. .0..1..1..1. .0..0..0..1
..0..1..0..0. .0..1..0..0. .1..0..0..0. .0..1..0..1. .0..1..0..1
..0..1..0..1. .1..0..1..1. .1..0..1..0. .1..1..0..1. .1..1..0..1
..1..1..0..0. .1..0..1..0. .1..0..1..0. .1..0..0..0. .0..0..1..0
CROSSREFS
Cf. A302623.
Sequence in context: A261846 A110215 A281465 * A302411 A303178 A250168
KEYWORD
nonn
AUTHOR
R. H. Hardin, Apr 10 2018
STATUS
approved