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 A199705 Number of -n..n arrays x(0..2) of 3 elements with zero sum and no two neighbors equal. 1
 6, 14, 32, 52, 82, 114, 156, 200, 254, 310, 376, 444, 522, 602, 692, 784, 886, 990, 1104, 1220, 1346, 1474, 1612, 1752, 1902, 2054, 2216, 2380, 2554, 2730, 2916, 3104, 3302, 3502, 3712, 3924, 4146, 4370, 4604, 4840, 5086, 5334, 5592, 5852, 6122, 6394, 6676 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS Row 3 of A199704. LINKS R. H. Hardin, Table of n, a(n) for n = 1..200 FORMULA Empirical: a(n) = 2*a(n-1) - 2*a(n-3) + a(n-4). Conjectures from Colin Barker, May 16 2018: (Start) G.f.: 2*x*(3 + x + 2*x^2) / ((1 - x)^3*(1 + x)). a(n) = n + 3*n^2 for n even. a(n) = 2 + n + 3*n^2 for n odd. (End) EXAMPLE Some solutions for n=5: ..1...-5....1....1....3...-1...-2....3....1....2....2...-5....3...-3...-3....4 ..3....3...-5....4....0...-4....3...-3...-1...-5....0....5...-2....4....0....1 .-4....2....4...-5...-3....5...-1....0....0....3...-2....0...-1...-1....3...-5 CROSSREFS Cf. A199704. Sequence in context: A024932 A273365 A271996 * A225972 A078836 A142875 Adjacent sequences:  A199702 A199703 A199704 * A199706 A199707 A199708 KEYWORD nonn AUTHOR R. H. Hardin, Nov 09 2011 STATUS approved

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Last modified August 25 21:00 EDT 2019. Contains 326324 sequences. (Running on oeis4.)