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URL: https://oeis.org/A281564

⇱ A281564 - OEIS

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A281564
Number of 2Xn 0..1 arrays with no element equal to more than two of its horizontal, diagonal or antidiagonal neighbors, with the exception of exactly two elements, and with new values introduced in order 0 sequentially upwards.
1
0, 0, 5, 18, 141, 602, 2180, 7006, 20979, 59698, 163635, 435900, 1135036, 2901852, 7307093, 18167506, 44683929, 108886702, 263208036, 631773802, 1507041943, 3575151970, 8439694735, 19835439712, 46433224508, 108305733064, 251797970649
OFFSET
1,3
COMMENTS
Row 2 of A281563.
LINKS
FORMULA
Empirical: a(n) = 7*a(n-1) -10*a(n-2) -29*a(n-3) +68*a(n-4) +67*a(n-5) -195*a(n-6) -108*a(n-7) +306*a(n-8) +132*a(n-9) -276*a(n-10) -96*a(n-11) +136*a(n-12) +32*a(n-13) -32*a(n-14) for n>15
EXAMPLE
Some solutions for n=4
..0..1..0..0. .0..0..0..1. .0..1..1..0. .0..1..1..0. .0..1..1..0
..0..0..1..0. .0..1..1..1. .1..1..1..0. .0..1..1..1. .0..0..0..0
CROSSREFS
Cf. A281563.
Sequence in context: A140296 A278172 A204252 * A291356 A091059 A352663
KEYWORD
nonn
AUTHOR
R. H. Hardin, Jan 24 2017
STATUS
approved