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A223455 Number of idempotent 3 X 3 -n..n matrices. 2
164, 848, 1928, 3752, 5624, 9920, 12632, 17084, 21656, 28952, 33248, 44072, 49280, 59480, 70712, 81392, 88112, 105416, 113072, 131312, 147248, 163592, 172688, 198824, 212744, 231944, 249272, 275192, 286928, 329528, 342416, 366320, 391376 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Row 3 of A223453.

LINKS

R. H. Hardin, Table of n, a(n) for n = 1..38

Project Euler, Problem 572: Idempotent matrices

EXAMPLE

Some solutions for n=3

..3.-2..0....1.-1..1....0.-3..3....0.-3..3....0..0..0....0..0..0....0..2..0

..3.-2..0...-3..3.-3....0..3.-3....0..1..0....2..3.-2...-3..3.-3....0..1..0

..2.-2..1...-3..3.-3....0..2.-2....0..0..1....2..3.-2...-2..2.-2....0..1..0

CROSSREFS

Cf. A223453.

Sequence in context: A105653 A233997 A233990 * A251197 A038670 A192993

Adjacent sequences:  A223452 A223453 A223454 * A223456 A223457 A223458

KEYWORD

nonn

AUTHOR

R. H. Hardin, Apr 09 2013

STATUS

approved

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Last modified April 22 09:59 EDT 2021. Contains 343174 sequences. (Running on oeis4.)