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A192714
Number of 13X2 integer matrices with each row summing to zero, row elements in nondecreasing order, rows in lexicographically nondecreasing order, and the sum of squares of the elements <= 2*n^2 (number of collections of 13 zero-sum 2-vectors with total modulus squared not more than 2*n^2, ignoring vector and component permutations)
1
2, 6, 19, 55, 140, 331, 732, 1533, 3055, 5857, 10824, 19386, 33743, 57293, 95044, 154445, 246197, 385697, 594416, 902641, 1351643, 1998191, 2918046, 4213843, 6019994, 8515367, 11930845, 16568416, 22815114, 31168260, 42253487, 56871045
OFFSET
1,1
COMMENTS
Column (13,2,n) of A192710
LINKS
EXAMPLE
Some solutions for 13X2 <= 2*4^2
.-3..3...-2..2...-2..2...-2..2...-2..2...-2..2...-3..3...-2..2...-2..2...-3..3
.-1..1....0..0...-2..2...-2..2...-2..2...-2..2...-1..1...-1..1...-1..1...-2..2
.-1..1....0..0...-1..1...-2..2...-2..2....0..0...-1..1...-1..1...-1..1...-1..1
.-1..1....0..0...-1..1...-1..1...-1..1....0..0...-1..1...-1..1...-1..1...-1..1
.-1..1....0..0...-1..1...-1..1...-1..1....0..0...-1..1...-1..1...-1..1....0..0
.-1..1....0..0...-1..1...-1..1....0..0....0..0...-1..1...-1..1...-1..1....0..0
.-1..1....0..0...-1..1...-1..1....0..0....0..0....0..0...-1..1...-1..1....0..0
..0..0....0..0...-1..1....0..0....0..0....0..0....0..0...-1..1...-1..1....0..0
..0..0....0..0...-1..1....0..0....0..0....0..0....0..0...-1..1....0..0....0..0
..0..0....0..0...-1..1....0..0....0..0....0..0....0..0...-1..1....0..0....0..0
..0..0....0..0....0..0....0..0....0..0....0..0....0..0....0..0....0..0....0..0
..0..0....0..0....0..0....0..0....0..0....0..0....0..0....0..0....0..0....0..0
..0..0....0..0....0..0....0..0....0..0....0..0....0..0....0..0....0..0....0..0
CROSSREFS
Sequence in context: A214948 A192713 A014559 * A027098 A183305 A192715
KEYWORD
nonn
AUTHOR
R. H. Hardin Jul 07 2011
STATUS
approved