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A281569 Number of 7Xn 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, 1508, 62882, 162919, 430995, 919632, 1818257, 3326246, 5744641, 9601436, 15859355, 26033851, 42510000, 69365630, 113056482, 183794484, 298249938, 483393766, 782278654, 1263834968, 2038915696, 3284498896, 5282364942 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,2
COMMENTS
Row 7 of A281563.
LINKS
FORMULA
Empirical: a(n) = 6*a(n-1) -15*a(n-2) +23*a(n-3) -30*a(n-4) +36*a(n-5) -34*a(n-6) +30*a(n-7) -36*a(n-8) +43*a(n-9) -42*a(n-10) +42*a(n-11) -40*a(n-12) +27*a(n-13) -18*a(n-14) +21*a(n-15) -21*a(n-16) +15*a(n-17) -12*a(n-18) +9*a(n-19) -3*a(n-20) +a(n-21) -3*a(n-22) +3*a(n-23) -a(n-24) for n>46
EXAMPLE
Some solutions for n=4
..0..0..1..1. .0..0..0..1. .0..0..0..0. .0..1..0..1. .0..0..1..0
..1..1..0..0. .1..1..1..0. .1..1..1..1. .0..1..0..1. .0..0..1..0
..0..1..0..1. .0..0..0..0. .0..1..0..0. .1..1..1..0. .1..1..0..1
..0..0..0..1. .1..0..1..0. .0..1..0..1. .0..0..1..0. .0..1..0..1
..1..1..1..0. .1..1..1..0. .1..1..0..1. .1..0..1..0. .0..1..1..1
..0..0..1..0. .0..0..1..0. .1..0..0..1. .1..0..1..1. .0..1..0..0
..0..0..1..1. .0..0..1..1. .1..0..0..1. .0..1..0..0. .1..1..0..1
CROSSREFS
Cf. A281563.
Sequence in context: A096021 A190032 A237319 * A252553 A237725 A200915
KEYWORD
nonn
AUTHOR
R. H. Hardin, Jan 24 2017
STATUS
approved

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Last modified May 20 14:08 EDT 2024. Contains 372717 sequences. (Running on oeis4.)