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 A221121 Number of n X 3 arrays of occupancy after each element stays put or moves to some horizontal or antidiagonal neighbor. 1
 8, 200, 4872, 118472, 2880520, 70036168, 1702839048, 41402332360, 1006644240392, 24475254623432, 595084206353160, 14468703925621448, 351787849605678088, 8553267228797150920, 207961646114893122312, 5056318842606537992392 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS Column 3 of A221125. LINKS R. H. Hardin, Table of n, a(n) for n = 1..124 FORMULA Empirical: a(n) = 26*a(n-1) - 41*a(n-2). Conjectures from Colin Barker, Aug 03 2018: (Start) G.f.: 8*x*(1 - x) / (1 - 26*x + 41*x^2). a(n) = ((13-8*sqrt(2))^n*(4-7*sqrt(2)) + (4+7*sqrt(2))*(13+8*sqrt(2))^n) / 41. (End) EXAMPLE Some solutions for n=3. ..2..1..0....2..1..0....1..1..1....1..1..0....1..0..1....0..1..1....1..2..0 ..0..4..0....2..1..0....0..2..0....2..1..0....1..2..0....1..2..0....1..1..0 ..1..0..1....2..0..1....3..0..1....3..1..0....2..1..1....1..1..2....1..3..0 CROSSREFS Cf. A221125. Sequence in context: A229265 A323562 A034861 * A264124 A317631 A309904 Adjacent sequences: A221118 A221119 A221120 * A221122 A221123 A221124 KEYWORD nonn AUTHOR R. H. Hardin, Jan 02 2013 STATUS approved

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Last modified December 4 08:59 EST 2023. Contains 367558 sequences. (Running on oeis4.)