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 A195233 Number of lower triangles of a 3 X 3 0..n array with each element differing from all of its diagonal, vertical, antidiagonal and horizontal neighbors by one or less. 1
 64, 155, 246, 337, 428, 519, 610, 701, 792, 883, 974, 1065, 1156, 1247, 1338, 1429, 1520, 1611, 1702, 1793, 1884, 1975, 2066, 2157, 2248, 2339, 2430, 2521, 2612, 2703, 2794, 2885, 2976, 3067, 3158, 3249, 3340, 3431, 3522, 3613, 3704, 3795, 3886, 3977 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS Row 3 of A195232. LINKS R. H. Hardin, Table of n, a(n) for n = 1..200 FORMULA Empirical: a(n) = 91*n - 27. Conjectures from Colin Barker, May 06 2018: (Start) G.f.: x*(64 + 27*x) / (1 - x)^2. a(n) = 2*a(n-1) - a(n-2) for n>2. (End) EXAMPLE Some solutions for n=4: ..2......1......0......2......1......3......2......0......4......3......0 ..2.3....2.1....0.1....1.1....0.0....2.2....2.1....0.1....3.3....4.3....0.0 ..2.3.3..1.1.2..0.1.1..2.2.1..0.0.0..2.2.1..2.1.1..1.0.0..3.4.4..3.3.4..0.1.1 CROSSREFS Cf. A195232. Sequence in context: A044315 A044696 A235120 * A086052 A044396 A044777 Adjacent sequences: A195230 A195231 A195232 * A195234 A195235 A195236 KEYWORD nonn AUTHOR R. H. Hardin, Sep 13 2011 STATUS approved

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Last modified March 28 23:19 EDT 2023. Contains 361596 sequences. (Running on oeis4.)