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A281052
Number of nX4 0..1 arrays with no element equal to more than one of its horizontal and antidiagonal neighbors, with the exception of exactly two elements, and with new values introduced in order 0 sequentially upwards.
1
1, 34, 239, 1022, 3416, 10112, 27635, 71419, 177320, 426696, 1002035, 2306828, 5224307, 11669686, 25762564, 56301813, 121961820, 262154625, 559637795, 1187392495, 2505484374, 5260557953, 10995496220, 22888340830, 47465895442
OFFSET
1,2
COMMENTS
Column 4 of A281056.
LINKS
FORMULA
Empirical: a(n) = 3*a(n-1) +3*a(n-2) -11*a(n-3) -9*a(n-4) +18*a(n-5) +17*a(n-6) -12*a(n-7) -15*a(n-8) +3*a(n-9) +6*a(n-10) -a(n-12) for n>14
EXAMPLE
Some solutions for n=4
..0..1..0..0. .0..0..0..1. .0..1..1..0. .0..0..0..1. .0..0..1..0
..0..1..1..1. .0..1..0..1. .0..0..0..1. .1..1..0..1. .1..1..0..1
..0..1..0..0. .0..0..0..1. .0..1..0..0. .0..1..0..0. .0..1..0..0
..0..1..0..1. .0..1..0..0. .0..1..1..0. .1..0..1..0. .0..1..0..1
CROSSREFS
Cf. A281056.
Sequence in context: A355884 A055716 A233300 * A020872 A302474 A183319
KEYWORD
nonn
AUTHOR
R. H. Hardin, Jan 13 2017
STATUS
approved