

A192713


Number of 12X2 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 12 zerosum 2vectors with total modulus squared not more than 2*n^2, ignoring vector and component permutations)


1



2, 6, 19, 53, 133, 310, 669, 1371, 2684, 5037, 9125, 16021, 27343, 45523, 74103, 118121, 184828, 284258, 430192, 641623, 944008, 1371445, 1968786, 2795325, 3927604, 5465114, 7534219, 10297413, 13958709, 18775675, 25067921, 33235421
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OFFSET

1,1


COMMENTS

Column (12,2,n) of A192710


LINKS

R. H. Hardin, Table of n, a(n) for n = 1..65


EXAMPLE

Some solutions for 12X2 <= 2*4^2
.2..2...2..2...2..2...1..1...2..2...2..2...1..1....0..0...2..2...1..1
.1..1...1..1...1..1...1..1...1..1...2..2...1..1....0..0...1..1...1..1
.1..1...1..1...1..1...1..1...1..1...2..2...1..1....0..0...1..1....0..0
.1..1...1..1...1..1...1..1...1..1....0..0...1..1....0..0...1..1....0..0
..0..0...1..1...1..1...1..1...1..1....0..0....0..0....0..0...1..1....0..0
..0..0....0..0...1..1...1..1...1..1....0..0....0..0....0..0...1..1....0..0
..0..0....0..0...1..1...1..1...1..1....0..0....0..0....0..0...1..1....0..0
..0..0....0..0...1..1...1..1...1..1....0..0....0..0....0..0...1..1....0..0
..0..0....0..0...1..1....0..0...1..1....0..0....0..0....0..0...1..1....0..0
..0..0....0..0...1..1....0..0...1..1....0..0....0..0....0..0...1..1....0..0
..0..0....0..0....0..0....0..0...1..1....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...1..1....0..0


CROSSREFS

Sequence in context: A192711 A192712 A214948 * A014559 A192714 A027098
Adjacent sequences: A192710 A192711 A192712 * A192714 A192715 A192716


KEYWORD

nonn


AUTHOR

R. H. Hardin Jul 07 2011


STATUS

approved



