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 A221274 Number of nX4 arrays of occupancy after each element moves to some horizontal, diagonal or antidiagonal neighbor, with every occupancy equal to zero or two 1
 1, 25, 100, 1089, 6724, 56644, 400689, 3122289, 23049601, 175350564, 1311815961, 9905822784, 74413292944, 560619075025, 4216817073121, 31746204178129, 238880949939076, 1798010762343849, 13531178521076836, 101839561889056996 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS Column 4 of A221275 LINKS R. H. Hardin, Table of n, a(n) for n = 1..21 FORMULA Empirical: a(n) = 7*a(n-1) +16*a(n-2) -105*a(n-3) +108*a(n-4) +10*a(n-5) -56*a(n-6) -53*a(n-7) +23*a(n-8) -6*a(n-9) +a(n-10) EXAMPLE Some solutions for n=4 ..0..2..2..0....0..2..2..0....0..0..2..2....0..0..2..0....2..2..2..0 ..2..0..0..0....2..0..0..2....2..2..0..0....0..2..2..2....0..2..0..2 ..0..2..2..0....2..2..0..2....0..0..2..2....2..0..2..2....0..0..2..0 ..0..2..2..2....0..0..2..0....0..2..2..0....0..2..0..0....2..2..0..0 CROSSREFS Sequence in context: A016850 A309779 A356533 * A042220 A114254 A042222 Adjacent sequences: A221271 A221272 A221273 * A221275 A221276 A221277 KEYWORD nonn AUTHOR R. H. Hardin Jan 09 2013 STATUS approved

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Last modified March 24 15:59 EDT 2023. Contains 361479 sequences. (Running on oeis4.)