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A266830
Number of nX2 arrays containing 2 copies of 0..n-1 with no element 1 greater than its north, west or northwest neighbor modulo n and the upper left element equal to 0.
0
1, 0, 1, 11, 314, 16904, 1344296, 145081212, 20235221346, 3536250581320, 756433785656967
OFFSET
1,4
COMMENTS
Column 2 of A266832.
EXAMPLE
Some solutions for n=5
..0..0....0..4....0..4....0..4....0..3....0..3....0..0....0..2....0..2....0..0
..3..2....2..2....4..2....3..3....0..2....0..2....3..2....2..4....4..2....4..4
..2..1....1..0....3..2....1..1....4..4....2..4....2..1....1..1....4..1....3..3
..4..4....1..3....1..1....0..4....3..1....1..4....4..4....0..3....3..1....2..1
..1..3....4..3....3..0....2..2....2..1....1..3....3..1....4..3....0..3....2..1
CROSSREFS
Cf. A266832.
Sequence in context: A090271 A267753 A233241 * A266029 A106827 A276977
KEYWORD
nonn
AUTHOR
R. H. Hardin, Jan 04 2016
STATUS
approved