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 A283951 Number of 2Xn 0..1 arrays with no 1 equal to more than three of its horizontal, diagonal and antidiagonal neighbors, with the exception of exactly one element. 1
 0, 0, 2, 16, 84, 408, 1926, 8776, 38912, 169456, 727914, 3091712, 13010668, 54334792, 225449486, 930278584, 3820249240, 15622389664, 63649588850, 258473068912, 1046543827972, 4226200851704, 17025631341974, 68440231400232 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,3 COMMENTS Row 2 of A283950. LINKS R. H. Hardin, Table of n, a(n) for n = 1..210 FORMULA Empirical: a(n) = 6*a(n-1) -7*a(n-2) +8*a(n-3) -31*a(n-4) -50*a(n-5) -61*a(n-6) -84*a(n-7) -36*a(n-8). Empirical g.f.: G.f.: 2*x^3*(1+x)^2/(-1+3*x+x^2+7*x^3+6*x^4)^2 . - R. J. Mathar, Mar 21 2017 EXAMPLE Some solutions for n=4 ..1..1..1..1. .1..0..1..0. .1..1..1..0. .1..1..0..1. .1..0..1..1 ..1..0..1..1. .1..1..1..0. .1..0..1..0. .0..1..1..1. .1..1..1..0 CROSSREFS Cf. A283950. Sequence in context: A207880 A207263 A207757 * A207340 A207768 A207891 Adjacent sequences:  A283948 A283949 A283950 * A283952 A283953 A283954 KEYWORD nonn AUTHOR R. H. Hardin, Mar 18 2017 STATUS approved

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Last modified December 8 05:11 EST 2021. Contains 349590 sequences. (Running on oeis4.)