A195888 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 <=32

1, 1, 9, 369, 68551, 65530899, 314737269521

Offset

1,3

Comments

Column 4 of A195892

Links

Table of n, a(n) for n=1..7.

Example

Some solutions for n=4
..0........0........0........0........0........0........0........0
..3-3.....-4.4.....-2.2......4-4......4-4.....-3.3.....-2.2......2-2
..1.3-4....2-3.1....2-1-1...-3.4-1....0.0.0....0.1-1....2.1-3...-4.4.0
.-4.0.4.0..2-1-1.0..0-1.1.0.-1.0.1.0.-4.4.0.0..3-4.1.0..0-3.3.0..2-2.0.0

Crossrefs

Sequence in context: A162133 A197179 A344338 * A162084 A195518 A302131

Adjacent sequences: A195885 A195886 A195887 * A195889 A195890 A195891

Keyword

nonn

Author

R. H. Hardin Sep 24 2011

Status

approved