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 zero-sum 2-vectors with total modulus squared not more than 2*n^2, ignoring vector and component permutations)

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

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