A224115 Number of idempotent 4X4 0..n matrices of rank 2.

282, 1434, 4182, 9762, 19110, 34602, 56982, 89766, 134298, 194262, 271074, 371478, 494346, 647358, 833226, 1057542, 1321482, 1636314, 1999926, 2425794, 2913678, 3472242, 4104942, 4828626

Offset

1,1

Links

Table of n, a(n) for n=1..24.

Example

Some solutions for n=3
..0..0..0..0....1..0..0..0....0..0..0..0....0..0..0..0....1..0..0..0
..1..1..0..0....0..1..1..0....1..1..0..0....1..1..0..0....0..1..0..0
..2..1..0..1....0..0..0..0....0..0..1..0....1..1..0..1....2..2..0..0
..1..0..0..1....0..3..3..0....0..0..1..0....0..0..0..1....0..3..0..0

Crossrefs

Row 4 of A224114.

Sequence in context: A250580 A252364 A345704 * A248459 A172627 A172725

Adjacent sequences: A224112 A224113 A224114 * A224116 A224117 A224118

Keyword

nonn,more

Author

R. H. Hardin, Apr 09 2013

Status

approved