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 A221196 Number of n X 3 arrays of occupancy after each element moves to some horizontal, diagonal or antidiagonal neighbor, with no occupancy greater than 2. 1
 2, 10, 46, 212, 976, 4492, 20672, 95128, 437752, 2014400, 9269632, 42655888, 196288736, 903257824, 4156502752, 19126892096, 88015820416, 405020564416, 1863774679808, 8576493051520, 39466269101440, 181611106939904 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS Column 3 of A221200. LINKS R. H. Hardin, Table of n, a(n) for n = 1..33 FORMULA Empirical: a(n) = 6*a(n-1) - 6*a(n-2) - 2*a(n-3). Empirical g.f.: 2*x*(1 - x - x^2) / (1 - 6*x + 6*x^2 + 2*x^3). - Colin Barker, Aug 04 2018 EXAMPLE Some solutions for n=3: ..0..2..0....0..2..0....1..2..0....1..2..1....1..2..1....1..2..0....0..2..1 ..1..2..2....0..2..2....0..2..1....1..2..0....0..2..1....1..2..0....0..2..2 ..0..2..0....0..2..1....0..2..1....0..2..0....0..2..0....0..2..1....0..2..0 CROSSREFS Cf. A221200. Sequence in context: A290923 A106709 A204091 * A137193 A006213 A137635 Adjacent sequences:  A221193 A221194 A221195 * A221197 A221198 A221199 KEYWORD nonn AUTHOR R. H. Hardin, Jan 04 2013 STATUS approved

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Last modified March 30 16:16 EDT 2020. Contains 333127 sequences. (Running on oeis4.)