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 A281207 Number of 3 X n 0..1 arrays with no element equal to more than one of its horizontal and antidiagonal neighbors, with the exception of exactly one element, and with new values introduced in order 0 sequentially upwards. 1
 0, 10, 56, 98, 176, 310, 537, 922, 1573, 2672, 4524, 7640, 12875, 21658, 36375, 61006, 102184, 170954, 285693, 476954, 795497, 1325596, 2207076, 3671788, 6103951, 10139930, 16833147, 27926522, 46302368, 76725022, 127066209, 210326170 (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) = 3*a(n-1) - a(n-2) - 3*a(n-3) + a(n-4) + a(n-5) for n>8. Empirical g.f.: x^2*(10 + 26*x - 60*x^2 - 32*x^3 + 38*x^4 + 11*x^5 - 5*x^6) / ((1 - x)*(1 - x - x^2)^2). - Colin Barker, Feb 18 2019 EXAMPLE Some solutions for n=4: ..0..0..1..0. .0..1..1..1. .0..0..1..0. .0..1..0..1. .0..1..0..1 ..1..0..1..0. .0..1..0..1. .1..1..1..0. .1..0..1..0. .1..0..1..0 ..1..0..0..1. .0..1..0..1. .0..0..1..0. .1..0..0..0. .1..0..0..1 CROSSREFS Row 3 of A281205. Sequence in context: A261848 A000814 A202071 * A228888 A137931 A053493 Adjacent sequences:  A281204 A281205 A281206 * A281208 A281209 A281210 KEYWORD nonn AUTHOR R. H. Hardin, Jan 17 2017 STATUS approved

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Last modified March 19 23:02 EDT 2019. Contains 321343 sequences. (Running on oeis4.)