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 A275402 Number of 3 X n 0..2 arrays with no element equal to any value at offset (-2,-1) (-2,0) or (-1,1) and new values introduced in order 0..2. 1
 3, 16, 84, 444, 2344, 12376, 65344, 345008, 1821600, 9617824, 50780928, 268117056, 1415625088, 7474326400, 39463524352, 208362556160, 1100128676352, 5808544139776, 30668398841856, 161925374911488, 854946069256192 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 LINKS R. H. Hardin, Table of n, a(n) for n = 1..210 FORMULA Empirical: a(n) = 4*a(n-1) + 6*a(n-2) + 4*a(n-3). Empirical g.f.: x*(3 + 4*x + 2*x^2) / (1 - 4*x - 6*x^2 - 4*x^3). - Colin Barker, Feb 04 2019 EXAMPLE Some solutions for n=4: ..0..1..2..2. .0..1..1..1. .0..0..1..1. .0..0..1..2. .0..1..0..0 ..0..0..0..1. .0..2..0..1. .2..0..0..0. .1..2..1..0. .0..2..1..1 ..2..2..0..1. .1..2..2..0. .1..1..2..2. .1..2..2..0. .1..2..2..2 CROSSREFS Row 3 of A275401. Sequence in context: A037584 A030983 A069429 * A026131 A026160 A025187 Adjacent sequences:  A275399 A275400 A275401 * A275403 A275404 A275405 KEYWORD nonn AUTHOR R. H. Hardin, Jul 26 2016 STATUS approved

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Last modified January 27 01:45 EST 2021. Contains 340443 sequences. (Running on oeis4.)