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 A221853 Number of 2 X n arrays of occupancy after each element stays put or moves to some horizontal, diagonal or antidiagonal neighbor, without consecutive moves in the same direction. 1
 1, 31, 302, 3437, 37155, 406612, 4434129, 48397883, 528123314, 5763315281, 62892896491, 686329748776, 7489683895265, 81732408497079, 891918279715066, 9733204380907645, 106215187016111667, 1159090627331995148 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS Row 2 of A221852. LINKS R. H. Hardin, Table of n, a(n) for n = 1..37 FORMULA Empirical: a(n) = 13*a(n-1) - 14*a(n-2) - 113*a(n-3) + 189*a(n-4) - 10*a(n-5) - 42*a(n-6) + 18*a(n-7) - 2*a(n-8). Empirical g.f.: x*(1 + 18*x - 87*x^2 + 58*x^3 + 16*x^4 - 8*x^5 - 2*x^6) / (1 - 13*x + 14*x^2 + 113*x^3 - 189*x^4 + 10*x^5 + 42*x^6 - 18*x^7 + 2*x^8). - Colin Barker, Aug 11 2018 EXAMPLE Some solutions for n=3: ..3..2..1....2..0..2....0..2..1....0..0..1....2..0..0....2..1..1....0..2..0 ..0..0..0....1..0..1....0..3..0....1..2..2....1..3..0....0..0..2....3..0..1 CROSSREFS Cf. A221852. Sequence in context: A279980 A001298 A027841 * A000500 A141912 A147297 Adjacent sequences:  A221850 A221851 A221852 * A221854 A221855 A221856 KEYWORD nonn AUTHOR R. H. Hardin, Jan 27 2013 STATUS approved

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Last modified October 21 07:03 EDT 2019. Contains 328292 sequences. (Running on oeis4.)