A192702 Number of 3X3 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 3 zero-sum 3-vectors with total modulus squared not more than 2*n^2, ignoring vector and component permutations)

2, 9, 36, 114, 308, 745, 1597, 3194, 5944, 10408, 17408, 28207, 43739, 66091, 97417, 139756, 197048, 273225, 370834, 497159, 658332, 859295, 1109567, 1420234, 1795384, 2253449, 2806737, 3464221, 4246712, 5179322, 6262896, 7537671, 9025226

Offset

1,1

Comments

Column (3,3,n) of A192710

Links

R. H. Hardin, Table of n, a(n) for n = 1..128

Example

Some solutions for 3X3 <= 2*4^2
.-2.-2..4...-2..0..2...-1.-1..2...-3..0..3...-2..0..2...-4..2..2...-2.-1..3
.-1.-1..2...-2..0..2...-1.-1..2...-2.-1..3...-1.-1..2...-1..0..1...-1.-1..2
.-1..0..1...-2..0..2...-1.-1..2....0..0..0...-1.-1..2....0..0..0...-1.-1..2

Crossrefs

Sequence in context: A086556 A319012 A192694 * A073989 A288834 A134759

Adjacent sequences: A192699 A192700 A192701 * A192703 A192704 A192705

Keyword

nonn

Author

R. H. Hardin Jul 07 2011

Status

approved