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A281395
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 one element, and with new values introduced in order 0 sequentially upwards.
1
0, 10, 131, 438, 1413, 3838, 10226, 26468, 66952, 166702, 409856, 997078, 2406401, 5765066, 13727694, 32525520, 76710590, 180193960, 421829583, 984396802, 2290726469, 5317276304, 12314336174, 28459103594, 65645569873, 151157660144
OFFSET
1,2
COMMENTS
Column 3 of A281400.
LINKS
FORMULA
Empirical: a(n) = 4*a(n-1) -4*a(n-2) +6*a(n-3) -18*a(n-4) +4*a(n-5) +15*a(n-6) -6*a(n-7) +31*a(n-8) -48*a(n-9) +32*a(n-10) +8*a(n-11) -48*a(n-12) +32*a(n-13) -16*a(n-14) for n>19
EXAMPLE
Some solutions for n=4
..0..0..0. .0..0..1. .0..1..1. .0..1..0. .0..0..0. .0..0..1. .0..0..1
..1..1..1. .1..0..0. .0..1..1. .1..1..0. .0..1..0. .1..0..1. .1..0..1
..0..0..1. .1..1..0. .0..0..1. .0..0..1. .1..0..1. .1..0..1. .0..1..1
..0..1..1. .0..1..0. .1..0..1. .1..1..1. .1..0..1. .0..1..1. .0..0..1
CROSSREFS
Cf. A281400.
Sequence in context: A292119 A113386 A302615 * A268786 A284196 A286723
KEYWORD
nonn
AUTHOR
R. H. Hardin, Jan 21 2017
STATUS
approved