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 A208254 Number of n X 4 0..2 arrays with new values 0..2 introduced in row major order and no element equal to more than one of its immediate leftward or upward neighbors. 1
 14, 768, 43344, 2445264, 137947632, 7782199824, 439026252912, 24767296501776, 1397226183866736, 78823339024454928, 4446752320207192176, 250859789016717819408, 14152043831975777230704, 798375640062491402594064 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS Column 4 of A208258. LINKS R. H. Hardin, Table of n, a(n) for n = 1..210 FORMULA Empirical: a(n) = 61*a(n-1) - 266*a(n-2) + 416*a(n-3) - 256*a(n-4) for n>5. Empirical g.f.: 2*x*(7 - 43*x + 110*x^2 - 128*x^3 + 64*x^4) / (1 - 61*x + 266*x^2 - 416*x^3 + 256*x^4). - Colin Barker, Jun 29 2018 EXAMPLE Some solutions for n=4 ..0..0..0..0....0..0..0..1....0..0..1..2....0..1..0..2....0..0..0..0 ..1..0..1..0....2..0..1..0....0..2..2..0....1..2..2..1....1..2..2..2 ..2..1..0..1....0..2..1..1....2..0..0..1....1..0..1..2....1..2..1..1 ..2..0..1..0....2..0..0..1....2..1..2..1....0..1..2..0....1..2..1..2 CROSSREFS Cf. A208258. Sequence in context: A103426 A203750 A232158 * A210817 A042519 A050983 Adjacent sequences:  A208251 A208252 A208253 * A208255 A208256 A208257 KEYWORD nonn AUTHOR R. H. Hardin, Feb 24 2012 STATUS approved

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Last modified June 29 23:00 EDT 2022. Contains 354913 sequences. (Running on oeis4.)