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 A281558 Number of nX3 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, 5, 68, 815, 4172, 18020, 62882, 201551, 605398, 1743548, 4863258, 13228596, 35268263, 92503663, 239307757, 611896213, 1548973531, 3887082301, 9679914966, 23942689688, 58864085078, 143936487738, 350238677040, 848456244849 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS Column 3 of A281563. LINKS R. H. Hardin, Table of n, a(n) for n = 1..210 FORMULA Empirical: a(n) = 6*a(n-1) -12*a(n-2) +17*a(n-3) -45*a(n-4) +60*a(n-5) -3*a(n-6) +33*a(n-8) -255*a(n-9) +303*a(n-10) -195*a(n-11) +105*a(n-12) +96*a(n-13) -348*a(n-14) +644*a(n-15) -528*a(n-16) +48*a(n-17) +304*a(n-18) -384*a(n-19) +192*a(n-20) -64*a(n-21) for n>29 EXAMPLE Some solutions for n=4 ..0..1..1. .0..1..1. .0..0..1. .0..1..1. .0..0..1. .0..1..1. .0..0..1 ..1..0..1. .1..1..0. .1..0..0. .1..0..1. .1..1..1. .1..0..0. .0..0..0 ..1..1..1. .1..0..0. .1..1..0. .1..1..1. .1..0..1. .1..0..0. .0..1..1 ..1..0..0. .1..0..0. .0..0..0. .1..0..1. .1..1..0. .1..1..0. .0..0..1 CROSSREFS Cf. A281563. Sequence in context: A003361 A336433 A099334 * A165396 A029812 A208562 Adjacent sequences:  A281555 A281556 A281557 * A281559 A281560 A281561 KEYWORD nonn AUTHOR R. H. Hardin, Jan 24 2017 STATUS approved

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Last modified November 29 09:18 EST 2020. Contains 338765 sequences. (Running on oeis4.)