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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 R. H. Hardin, Table of n, a(n) for n = 1..150 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 Adjacent sequences: A281566 A281567 A281568 * A281570 A281571 A281572 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.)