A195891 Number of lower triangles of an n X n integer array with all row and column sums zero and all row and column sums of squares <=98

1, 1, 15, 1695, 1686561, 15120998539

Offset

1,3

Comments

Column 7 of A195892

Links

Table of n, a(n) for n=1..6.

Example

Some solutions for n=4
..0........0........0........0........0........0........0........0
.-3.3.....-3.3......2-2.....-5.5......2-2.....-3.3......1-1......5-5
..5.1-6....7.0-7...-5.6-1....7.0-7...-3.6-3...-3-2.5....4-4.0....0.7-7
.-2-4.6.0.-4-3.7.0..3-4.1.0.-2-5.7.0..1-4.3.0..6-1-5.0.-5.5.0.0.-5-2.7.0

Crossrefs

Sequence in context: A205423 A263600 A208860 * A195521 A122184 A069450

Adjacent sequences: A195888 A195889 A195890 * A195892 A195893 A195894

Keyword

nonn

Author

R. H. Hardin Sep 24 2011

Status

approved