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 A280481 Number of 2 X n 0..2 arrays with no element unequal to a strict majority of its horizontal and antidiagonal neighbors, with the exception of exactly two elements, and with new values introduced in order 0 sequentially upwards. 1
 0, 6, 22, 63, 162, 381, 884, 1995, 4478, 9913, 21832, 47687, 103666, 224117, 482556, 1034819, 2211686, 4712113, 10011696, 21217471, 44862298, 94656621, 199333092, 419016123, 879354062, 1842593961, 3855445784, 8056377655, 16813670338 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 LINKS R. H. Hardin, Table of n, a(n) for n = 1..210 FORMULA Empirical: a(n) = 5*a(n-1) - 4*a(n-2) - 14*a(n-3) + 19*a(n-4) + 13*a(n-5) - 22*a(n-6) - 4*a(n-7) + 8*a(n-8) for n>10. Empirical g.f.: x^2*(6 - 8*x - 23*x^2 + 19*x^3 + 17*x^4 + 13*x^5 + 16*x^6 - 16*x^7 - 40*x^8) / ((1 - x)^2*(1 + x)^3*(1 - 2*x)^3). - Colin Barker, Feb 13 2019 EXAMPLE Some solutions for n=4: ..0..0..0..1. .0..1..0..0. .0..0..1..1. .0..1..1..1. .0..0..1..2 ..0..1..1..1. .1..0..0..0. .0..2..2..2. .1..2..2..2. .0..1..1..1 CROSSREFS Row 2 of A280480. Sequence in context: A258474 A120477 A053739 * A055797 A001925 A002663 Adjacent sequences:  A280478 A280479 A280480 * A280482 A280483 A280484 KEYWORD nonn AUTHOR R. H. Hardin, Jan 04 2017 STATUS approved

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Last modified January 17 06:12 EST 2022. Contains 350378 sequences. (Running on oeis4.)