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A195892 T(n,k) = Number of lower triangles of an n X n integer array with all row and column sums zero and all row and column sums of squares <= 2k^2. 10
1, 1, 1, 1, 1, 3, 1, 1, 5, 15, 1, 1, 7, 65, 83, 1, 1, 9, 175, 1349, 591, 1, 1, 11, 369, 14831, 90013, 5281, 1, 1, 13, 671, 68551, 4857647, 17612909, 56249, 1, 1, 15, 1105, 241221, 65530899, 5181491667, 7690681987, 704129, 1, 1, 17, 1695, 680115, 584257875 (list; table; graph; refs; listen; history; text; internal format)
OFFSET
1,6
COMMENTS
Table starts
......1..........1..........1............1.........1......1....1..1.1.1
......1..........1..........1............1.........1......1....1..1.1
......3..........5..........7............9........11.....13...15.17
.....15.........65........175..........369.......671...1105.1695
.....83.......1349......14831........68551....241221.680115
....591......90013....4857647.....65530899.584257875
...5281...17612909.5181491667.314737269521
..56249.7690681987
.704129
LINKS
EXAMPLE
Some solutions for n=5 k=4
..0..........0..........0..........0..........0..........0..........0
.-1.1........1-1.......-4.4........3-3........1-1........2-2........3-3
.-2.1.1.....-2.4-2......3-3.0......0.3-3.....-2.4-2.....-4.3.1......0-1.1
..0-1-1.2...-2-1.2.1....1-1-3.3...-1-1.0.2....0-2-1.3....1-2.0.1....1.0-1.0
..3-1.0-2.0..3-2.0-1.0..0.0.3-3.0.-2.1.3-2.0..1-1.3-3.0..1.1-1-1.0.-4.4.0.0.0
CROSSREFS
Sequence in context: A335333 A341470 A293796 * A195522 A273169 A273167
KEYWORD
nonn,tabl
AUTHOR
R. H. Hardin, Sep 24 2011
STATUS
approved

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Last modified March 28 10:55 EDT 2024. Contains 371241 sequences. (Running on oeis4.)