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 A280227 Number of n X 2 0..1 arrays with no element unequal to a strict majority of its king-move neighbors, with the exception of exactly one element, and with new values introduced in order 0 sequentially upwards. 1
 0, 4, 6, 8, 14, 24, 42, 72, 124, 212, 362, 616, 1046, 1772, 2996, 5056, 8518, 14328, 24066, 40368, 67628, 113164, 189154, 315848, 526894, 878164, 1462372, 2433272, 4045694, 6721752, 11160282, 18517656, 30706396, 50888132, 84287066, 139531816 (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) = 2*a(n-1) + a(n-2) - 2*a(n-3) - a(n-4) for n>7. Empirical g.f.: x^2*(1 - x)*(1 + x)*(2 - x - 2*x^2 - x^3) / (1 - x - x^2)^2. - Colin Barker, Feb 13 2019 EXAMPLE All solutions for n=4: ..0..0. .0..1. .0..0. .0..0. .0..0. .0..0. .0..1. .0..0 ..0..1. .1..1. .0..0. .0..0. .0..0. .1..0. .0..0. .0..0 ..0..0. .1..1. .0..1. .1..0. .0..0. .0..0. .0..0. .0..0 ..0..0. .1..1. .0..0. .0..0. .1..0. .0..0. .0..0. .0..1 CROSSREFS Column 2 of A280233. Sequence in context: A116897 A293763 A246324 * A181978 A302636 A000937 Adjacent sequences:  A280224 A280225 A280226 * A280228 A280229 A280230 KEYWORD nonn AUTHOR R. H. Hardin, Dec 29 2016 STATUS approved

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Last modified March 28 11:49 EDT 2020. Contains 333083 sequences. (Running on oeis4.)