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 A198662 Number of nX1 0..4 arrays with values 0..4 introduced in row major order and each element equal to one or two horizontal and vertical neighbors 2
 0, 1, 1, 2, 3, 6, 11, 23, 47, 103, 226, 517, 1194, 2830, 6778, 16498, 40501, 100420, 250513, 628749, 1584525, 4007957, 10164528, 25835883, 65777232, 167694004, 427960360, 1093068944, 2793604179, 7143313914, 18272673575, 46755936515 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,4 COMMENTS Column 1 of A198669 LINKS R. H. Hardin, Table of n, a(n) for n = 1..200 FORMULA Empirical: a(n) = 4*a(n-1) +a(n-2) -17*a(n-3) +6*a(n-4) +21*a(n-5) -6*a(n-6) -8*a(n-7) for n>8 EXAMPLE All solutions for n=5 ..0....0....0 ..0....0....0 ..1....0....0 ..1....0....1 ..1....0....1 CROSSREFS Sequence in context: A036656 A199142 A090344 * A198620 A198648 A198655 Adjacent sequences:  A198659 A198660 A198661 * A198663 A198664 A198665 KEYWORD nonn AUTHOR R. H. Hardin Oct 28 2011 STATUS approved

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