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 A221162 Number of n X 2 arrays of occupancy after each element stays put or moves to some horizontal, vertical or antidiagonal neighbor. 1
 3, 33, 352, 3721, 39254, 413908, 4363921, 46008619, 485064009, 5113971944, 53915979657, 568429529006, 5992882377940, 63182219138721, 666122336505939, 7022845559348401, 74040993741513520, 780605056433123273 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS Column 2 of A221165. LINKS R. H. Hardin, Table of n, a(n) for n = 1..23 FORMULA Empirical: a(n) = 13*a(n-1) - 26*a(n-2) + a(n-3). Empirical g.f.: x*(3 - 6*x + x^2) / (1 - 13*x + 26*x^2 - x^3). - Colin Barker, Aug 04 2018 EXAMPLE Some solutions for n=3: ..0..0....3..1....1..0....0..0....0..0....2..0....1..0....0..2....3..1....0..3 ..3..0....0..1....2..2....2..1....3..1....2..1....0..3....0..0....0..0....1..1 ..2..1....0..1....1..0....3..0....1..1....1..0....2..0....4..0....2..0....1..0 CROSSREFS Cf. A221165. Sequence in context: A002277 A332087 A001507 * A231594 A075835 A077698 Adjacent sequences: A221159 A221160 A221161 * A221163 A221164 A221165 KEYWORD nonn AUTHOR R. H. Hardin, Jan 03 2013 STATUS approved

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Last modified May 20 10:51 EDT 2024. Contains 372712 sequences. (Running on oeis4.)