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 A229514 Number of n X 1 0..2 arrays of the median of the corresponding element, the element to the east and the element to the south in a larger (n+1) X 2 0..2 array without adjacent equal elements in the latter. 1
 3, 7, 17, 39, 91, 211, 491, 1141, 2653, 6167, 14337, 33329, 77481, 180121, 418731, 973431, 2262953, 5260727, 12229707, 28430619, 66093171, 153647981, 357188221, 830361871, 1930357153, 4487535937, 10432255377, 24252051409, 56379179411 (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) = 2*a(n-1) + a(n-2) - a(n-3) + a(n-4). Empirical g.f.: x*(3 + x + x^3) / ((1 + x)*(1 - 3*x + 2*x^2 - x^3)). - Colin Barker, Sep 18 2018 EXAMPLE Some solutions for n=3: ..1....2....0....1....0....1....0....1....2....1....0....2....2....1....1....2 ..0....0....2....2....2....1....1....2....0....1....1....1....1....0....1....1 ..1....1....0....0....1....1....1....1....2....2....2....1....2....2....0....0 CROSSREFS Column 1 of A229521. Sequence in context: A157029 A191825 A342600 * A077927 A005197 A147142 Adjacent sequences: A229511 A229512 A229513 * A229515 A229516 A229517 KEYWORD nonn AUTHOR R. H. Hardin, Sep 25 2013 STATUS approved

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Last modified December 3 21:20 EST 2023. Contains 367540 sequences. (Running on oeis4.)