A221311 T(n,k)=Number of idempotent n X n -k..k matrices of rank 1

1, 1, 10, 1, 26, 87, 1, 42, 447, 740, 1, 58, 999, 6820, 6285, 1, 74, 1935, 20708

Offset

1,3

Comments

Table starts

....1....1.....1....1..1.1

...10...26....42...58.74

...87..447...999.1935

..740.6820.20708

.6285

Links

Table of n, a(n) for n=1..19.

Example

Some solutions for n=3 k=4
..0.-3.-4....2.-1..1....4..4.-4....0..0..4...-2..3..4....1..2..2...-4.-4.-1
..0.-3.-4....0..0..0...-4.-4..4....0..0.-4...-2..3..4...-2.-4.-4....4..4..1
..0..3..4...-2..1.-1...-1.-1..1....0..0..1....0..0..0....2..4..4....4..4..1

Crossrefs

Row 2 is A223451

Sequence in context: A243002 A050999 A223450 * A361949 A070246 A085044

Adjacent sequences: A221308 A221309 A221310 * A221312 A221313 A221314

Keyword

nonn,tabl

Author

R. H. Hardin Apr 10 2013

Status

approved