A223454 Number of idempotent 2 X 2 -n..n matrices.

12, 28, 44, 60, 76, 108, 124, 140, 156, 188, 204, 236, 252, 284, 316, 332, 348, 380, 396, 428, 460, 492, 508, 540, 556, 588, 604, 636, 652, 716, 732, 748, 780, 812, 844, 876, 892, 924, 956, 988, 1004, 1068, 1084, 1116, 1148, 1180, 1196, 1228, 1244, 1276, 1308, 1340

Offset

1,1

Comments

Row 2 of A223453.

Links

R. H. Hardin, Table of n, a(n) for n = 1..210

Example

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

Crossrefs

Cf. A223453.

Sequence in context: A044454 A098502 A158953 * A107707 A183053 A126195

Adjacent sequences: A223451 A223452 A223453 * A223455 A223456 A223457

Keyword

nonn

Author

R. H. Hardin, Apr 09 2013

Status

approved