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A281558
Number of nX3 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, 5, 68, 815, 4172, 18020, 62882, 201551, 605398, 1743548, 4863258, 13228596, 35268263, 92503663, 239307757, 611896213, 1548973531, 3887082301, 9679914966, 23942689688, 58864085078, 143936487738, 350238677040, 848456244849
OFFSET
1,2
COMMENTS
Column 3 of A281563.
LINKS
FORMULA
Empirical: a(n) = 6*a(n-1) -12*a(n-2) +17*a(n-3) -45*a(n-4) +60*a(n-5) -3*a(n-6) +33*a(n-8) -255*a(n-9) +303*a(n-10) -195*a(n-11) +105*a(n-12) +96*a(n-13) -348*a(n-14) +644*a(n-15) -528*a(n-16) +48*a(n-17) +304*a(n-18) -384*a(n-19) +192*a(n-20) -64*a(n-21) for n>29
EXAMPLE
Some solutions for n=4
..0..1..1. .0..1..1. .0..0..1. .0..1..1. .0..0..1. .0..1..1. .0..0..1
..1..0..1. .1..1..0. .1..0..0. .1..0..1. .1..1..1. .1..0..0. .0..0..0
..1..1..1. .1..0..0. .1..1..0. .1..1..1. .1..0..1. .1..0..0. .0..1..1
..1..0..0. .1..0..0. .0..0..0. .1..0..1. .1..1..0. .1..1..0. .0..0..1
CROSSREFS
Cf. A281563.
Sequence in context: A363401 A336433 A099334 * A165396 A029812 A208562
KEYWORD
nonn
AUTHOR
R. H. Hardin, Jan 24 2017
STATUS
approved