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A201721 Number of n X n 0..4 arrays with rows and columns lexicographically nondecreasing and no element equal to the number of horizontal and vertical neighbors equal to itself 0
4, 90, 19827, 56836178, 1692459595971, 545947219624185244 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
COMMENTS
Diagonal of A201729
LINKS
EXAMPLE
Some solutions for n=3
..1..2..4....1..1..2....0..1..3....1..2..4....0..2..3....2..3..4....0..1..4
..3..4..2....1..1..3....0..3..1....3..0..0....0..4..2....3..1..2....0..4..3
..3..4..2....2..4..1....1..4..3....3..0..0....2..4..1....3..4..2....0..4..4
CROSSREFS
Sequence in context: A202918 A146506 A202575 * A374158 A195559 A195551
KEYWORD
nonn
AUTHOR
R. H. Hardin Dec 04 2011
STATUS
approved

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Last modified July 24 13:53 EDT 2024. Contains 374584 sequences. (Running on oeis4.)