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 A198508 Number of 2n X 2 0..4 arrays with values 0..4 introduced in row major order and each element unequal to exactly two horizontal and vertical neighbors. 1
 4, 59, 1626, 52065, 1720080, 57202471, 1905005414, 63461666189, 2114248706396, 70438021997715, 2346711308830450, 78183030527210041, 2604746159812022824, 86779736758694997119, 2891154190334815424766, 96321709194421413316965 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS Column 1 of A198511. LINKS R. H. Hardin, Table of n, a(n) for n = 1..200 FORMULA Empirical: a(n) = 51*a(n-1) -691*a(n-2) +3601*a(n-3) -7056*a(n-4) +4096*a(n-5). Empirical g.f.: x*(4 - 145*x + 1381*x^2 - 4496*x^3 + 4096*x^4) / ((1 - x)*(1 - 9*x + 16*x^2)*(1 - 41*x + 256*x^2)). - Colin Barker, May 14 2018 EXAMPLE Some solutions for n=3: ..0..1....0..1....0..1....0..1....0..1....0..1....0..1....0..1....0..1....0..1 ..2..2....2..3....2..2....2..2....1..2....2..3....1..0....1..2....2..2....2..2 ..3..3....2..3....3..3....1..1....1..2....2..3....1..0....1..2....3..3....3..1 ..1..0....1..1....2..2....0..3....2..0....1..2....2..2....2..3....0..0....3..1 ..1..0....4..4....1..1....0..3....2..0....1..2....3..3....2..3....4..4....4..4 ..4..3....1..3....3..2....2..1....3..1....4..3....0..1....3..1....1..0....3..1 CROSSREFS Cf. A198511. Sequence in context: A257069 A199107 A280668 * A126754 A264820 A194534 Adjacent sequences: A198505 A198506 A198507 * A198509 A198510 A198511 KEYWORD nonn AUTHOR R. H. Hardin, Oct 25 2011 STATUS approved

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Last modified August 5 11:26 EDT 2024. Contains 374950 sequences. (Running on oeis4.)