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Number of nX2 arrays containing 2 copies of 0..n-1 with no equal vertical or antidiagonal neighbors and new values introduced sequentially from 0.
0

%I #5 Aug 12 2016 07:04:20

%S 1,1,4,23,209,2301,29992,450525,7666097,145748085,3062086652,

%T 70451319403,1761725152737,47575849111097,1379912569740752,

%U 42782608276446713,1411969570132526241,49423093937535984041

%N Number of nX2 arrays containing 2 copies of 0..n-1 with no equal vertical or antidiagonal neighbors and new values introduced sequentially from 0.

%C Column 2 of A265679.

%e Some solutions for n=4

%e ..0..1....0..1....0..1....0..1....0..1....0..1....0..1....0..1....0..1....0..1

%e ..2..0....2..3....2..0....2..2....2..3....2..0....2..0....2..2....2..3....2..2

%e ..3..2....1..0....3..3....1..0....1..0....3..3....1..2....3..3....0..2....3..3

%e ..1..3....3..2....2..1....3..3....2..3....1..2....3..3....0..1....1..3....1..0

%Y Cf. A265679.

%K nonn

%O 1,3

%A _R. H. Hardin_, Dec 13 2015