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 A281693 T(n,k)=Number of nXk 0..2 arrays with no element equal to more than one of its horizontal, diagonal or antidiagonal neighbors, with the exception of exactly two elements, and with new values introduced in order 0 sequentially upwards. 8
 0, 0, 0, 0, 0, 0, 1, 6, 15, 0, 2, 272, 847, 222, 0, 9, 2516, 14575, 19326, 2348, 0, 34, 19168, 172398, 402470, 293814, 21302, 0, 124, 120824, 1900616, 7497214, 8944910, 3714629, 176125, 0, 432, 692320, 17698286, 126719222, 269206287, 173467508, 42265965 (list; table; graph; refs; listen; history; text; internal format)
 OFFSET 1,8 COMMENTS Table starts .0........0..........0............1.............2..............9.............34 .0........0..........6..........272..........2516..........19168.........120824 .0.......15........847........14575........172398........1900616.......17698286 .0......222......19326.......402470.......7497214......126719222.....1847808312 .0.....2348.....293814......8944910.....269206287.....7098401706...164629898128 .0....21302....3714629....173467508....8480641650...352593003706.13101015889336 .0...176125...42265965...3105145787..247006584444.16285953756462 .0..1370378..449985840..52667675560.6815559005187 .0.10206549.4571830360.858903297578 LINKS R. H. Hardin, Table of n, a(n) for n = 1..83 FORMULA Empirical for column k: k=1: a(n) = a(n-1) k=2: [order 12] k=3: [order 15] for n>20 k=4: [order 48] for n>56 Empirical for row n: n=1: a(n) = 6*a(n-1) -6*a(n-2) -16*a(n-3) +12*a(n-4) +24*a(n-5) +8*a(n-6) for n>10 n=2: [order 12] for n>15 n=3: [order 40] for n>45 EXAMPLE Some solutions for n=3 k=4 ..0..1..1..0. .0..1..2..2. .0..1..1..0. .0..1..2..0. .0..0..1..2 ..2..1..0..0. .2..0..0..0. .1..0..1..0. .1..2..0..1. .2..0..1..2 ..2..0..2..2. .1..0..2..0. .1..2..2..1. .0..1..2..1. .1..0..1..1 CROSSREFS Column 2 is A279530. Row 1 is A280309. Sequence in context: A263695 A158965 A284075 * A013314 A328339 A019306 Adjacent sequences:  A281690 A281691 A281692 * A281694 A281695 A281696 KEYWORD nonn,tabl AUTHOR R. H. Hardin, Jan 27 2017 STATUS approved

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Last modified October 31 08:46 EDT 2020. Contains 338101 sequences. (Running on oeis4.)