A192691 Number of 1X4 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 1 zero-sum 4-vectors with total modulus squared not more than 2*n^2, ignoring vector and component permutations)

2, 6, 15, 26, 45, 72, 105, 150, 206, 273, 353, 446, 560, 687, 834, 998, 1182, 1388, 1618, 1875, 2156, 2463, 2797, 3151, 3551, 3978, 4434, 4923, 5448, 6009, 6604, 7243, 7925, 8639, 9404, 10198, 11051, 11943, 12887, 13873, 14909, 16001, 17135, 18332, 19584

Offset

1,1

Comments

Column (1,4,n) of A192710

Links

R. H. Hardin, Table of n, a(n) for n = 1..200

Example

Some solutions for 1X4 <= 2*4^2
.-1..0..0..1...-2..0..0..2...-1.-1.-1..3...-2..0..1..1...-3.-1..0..4

Crossrefs

Sequence in context: A091766 A269706 A293402 * A360405 A256313 A380921

Adjacent sequences: A192688 A192689 A192690 * A192692 A192693 A192694

Keyword

nonn

Author

R. H. Hardin Jul 07 2011

Status

approved