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 A189274 Number of nX3 array permutations with each element not moved or moved diagonally or antidiagonally by one 3
 1, 9, 45, 225, 1125, 5625, 28125, 140625, 703125, 3515625, 17578125, 87890625, 439453125, 2197265625, 10986328125, 54931640625, 274658203125, 1373291015625, 6866455078125, 34332275390625, 171661376953125, 858306884765625, 4291534423828125, 21457672119140625 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS Column 3 of A189280 LINKS R. H. Hardin, Table of n, a(n) for n = 1..200 FORMULA Empirical: a(n) = 5*a(n-1) for n>2 Apparently, the O.g.f. is x*(1+4x)/(1-5x). - Philippe Deléham, Feb 25 2012 Apparently : a(n) = Sum_{k, 1<=k<=n} A207628(n,k)*2^(k-1). - Philippe Deléham, Feb 25 2012 EXAMPLE Some solutions for 4X3 ..0..1..4....0..1..4....4..5..2....4..1..2....0..5..2....0..5..2....0..5..2 ..3..2..5....3..2..5....3..0..1....3..0..5....3..8..1....7..4..1....3..4..1 .10.11..8....6..7..8...10.11..8....6..9.10....6.11..4...10..3..8....6..7..8 ..9..6..7....9.10.11....9..6..7....7..8.11....9.10..7....9..6.11....9.10.11 MATHEMATICA Join[{1}, LinearRecurrence[{5}, {9}, 70]] (* From Vladimir Joseph Stephan Orlovsky, Feb 26 2012 *) CROSSREFS Sequence in context: A024209 A179855 A180796 * A026092 A054628 A132133 Adjacent sequences:  A189271 A189272 A189273 * A189275 A189276 A189277 KEYWORD nonn AUTHOR R. H. Hardin Apr 19 2011 STATUS approved

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