A192708 Number of 8X2 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 8 zero-sum 2-vectors with total modulus squared not more than 2*n^2, ignoring vector and component permutations)

2, 6, 18, 43, 97, 199, 385, 707, 1235, 2072, 3383, 5336, 8218, 12341, 18215, 26362, 37488, 52464, 72546, 98944, 133305, 177633, 234514, 306557, 397175, 510188, 650637, 823774, 1035586, 1293255, 1606070, 1982596, 2433768, 2972209, 3612860

Offset

1,1

Comments

Column (8,2,n) of A192710

Links

R. H. Hardin, Table of n, a(n) for n = 1..125

Example

Some solutions for 8X2 <= 2*4^2
.-1..1...-2..2...-1..1...-1..1...-1..1...-1..1...-3..3...-3..3...-2..2...-1..1
.-1..1...-1..1...-1..1....0..0...-1..1...-1..1...-1..1...-2..2...-2..2...-1..1
.-1..1...-1..1....0..0....0..0...-1..1...-1..1...-1..1...-1..1...-1..1...-1..1
..0..0...-1..1....0..0....0..0...-1..1...-1..1...-1..1...-1..1...-1..1...-1..1
..0..0...-1..1....0..0....0..0...-1..1...-1..1...-1..1...-1..1...-1..1...-1..1
..0..0....0..0....0..0....0..0...-1..1...-1..1...-1..1....0..0...-1..1...-1..1
..0..0....0..0....0..0....0..0....0..0...-1..1....0..0....0..0...-1..1...-1..1
..0..0....0..0....0..0....0..0....0..0....0..0....0..0....0..0....0..0...-1..1

Crossrefs

Sequence in context: A195584 A225316 A272934 * A233531 A320303 A319415

Adjacent sequences: A192705 A192706 A192707 * A192709 A192710 A192711

Keyword

nonn

Author

R. H. Hardin Jul 07 2011

Status

approved