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 A268255 Number of length-(n+1) 0..2 arrays with new repeated values introduced in sequential order starting with zero. 1
 7, 17, 42, 106, 273, 717, 1918, 5218, 14413, 40349, 114282, 326938, 943257, 2740797, 8010982, 23529346, 69385813, 205282157, 608959218, 1810358938, 5391414273, 16078923309, 48007516942, 143470822498, 429083952157, 1284051486077 (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) = 7*a(n-1) - 15*a(n-2) + 7*a(n-3) + 6*a(n-4). Conjectures from Colin Barker, Jan 11 2019: (Start) G.f.: x*(7 - 32*x + 28*x^2 + 18*x^3) / ((1 - 2*x)*(1 - 3*x)*(1 - 2*x - x^2)). a(n) = 2^n + 3^n/2 + (3/4-1/sqrt(2))*(1-sqrt(2))^n + (3/4+1/sqrt(2))*(1+sqrt(2))^n. (End) EXAMPLE Some solutions for n=8: ..0....1....1....0....0....1....0....0....2....1....0....1....2....0....0....1 ..0....0....0....0....0....0....0....2....0....2....1....2....1....1....0....0 ..2....0....0....2....0....1....1....0....0....0....2....1....2....0....1....2 ..0....1....0....0....2....0....0....0....0....0....1....2....1....0....0....0 ..1....1....1....1....0....2....0....0....1....2....2....0....0....2....0....2 ..0....1....2....1....2....0....1....1....1....1....1....0....1....1....1....1 ..1....1....1....0....0....0....0....0....1....0....2....1....0....0....1....0 ..0....1....2....1....2....2....2....0....2....1....0....0....0....1....1....0 ..2....1....0....0....1....1....1....1....2....0....0....2....1....1....1....1 CROSSREFS Column 2 of A268261. Sequence in context: A184862 A194772 A193546 * A124965 A253973 A200080 Adjacent sequences: A268252 A268253 A268254 * A268256 A268257 A268258 KEYWORD nonn AUTHOR R. H. Hardin, Jan 29 2016 STATUS approved

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Last modified October 1 11:02 EDT 2023. Contains 365819 sequences. (Running on oeis4.)