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A248838
Number of length n arrays x(i), i=1..n with x(i) in 0..i and no value appearing more than 4 times
2
2, 6, 24, 120, 718, 4994, 39556, 351320, 3456742, 37314126, 438366374, 5567209930, 75995663398, 1109556555434, 17252609166736, 284620418911180, 4965138989585412, 91317809653363376, 1765937111915469414
OFFSET
1,1
COMMENTS
Column 4 of A248842
LINKS
EXAMPLE
Some solutions for n=6
..0....1....1....1....0....0....1....0....0....1....0....1....1....0....1....1
..0....2....2....0....0....2....0....2....2....0....2....1....1....2....0....1
..3....2....2....0....2....2....3....2....0....3....1....0....2....2....1....3
..3....0....3....3....3....2....1....2....0....0....0....4....0....1....0....0
..0....5....0....2....2....1....2....2....4....3....2....0....5....4....1....1
..3....4....5....1....6....5....5....5....6....2....1....1....5....4....0....2
CROSSREFS
Sequence in context: A164872 A226437 A224287 * A364231 A364234 A052398
KEYWORD
nonn
AUTHOR
R. H. Hardin, Oct 15 2014
STATUS
approved