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 A221883 Number of n X 2 arrays of occupancy after each element stays put or moves to some horizontal, vertical or antidiagonal neighbor, without consecutive moves in the same direction. 1
 3, 33, 326, 3223, 31832, 314426, 3105733, 30676867, 303010527, 2992984402, 29563182686, 292010132356, 2884328060800, 28489930453209, 281409090823688, 2779616346494657, 27455641219994600, 271192906082774221 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS Column 2 of A221886. LINKS R. H. Hardin, Table of n, a(n) for n = 1..55 FORMULA Empirical: a(n) = 7*a(n-1) + 27*a(n-2) + 16*a(n-3) - 18*a(n-4) - 13*a(n-5) + 5*a(n-6) + 3*a(n-7) - a(n-8). Empirical g.f.: x*(3 + 12*x + 14*x^2 + 2*x^3 - 5*x^4 - 2*x^5 + x^6) / (1 - 7*x - 27*x^2 - 16*x^3 + 18*x^4 + 13*x^5 - 5*x^6 - 3*x^7 + x^8). - Colin Barker, Aug 11 2018 EXAMPLE Some solutions for n=3: ..1..2....0..3....0..3....0..2....1..0....0..1....1..1....1..1....1..0....0..1 ..0..0....0..1....0..3....0..2....1..1....2..0....0..2....1..0....3..1....3..1 ..0..3....0..2....0..0....2..0....1..2....0..3....0..2....0..3....1..0....0..1 CROSSREFS Cf. A221886. Sequence in context: A097486 A121515 A362478 * A002277 A332087 A001507 Adjacent sequences: A221880 A221881 A221882 * A221884 A221885 A221886 KEYWORD nonn AUTHOR R. H. Hardin, Jan 30 2013 STATUS approved

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Last modified August 10 18:57 EDT 2024. Contains 375058 sequences. (Running on oeis4.)