A222823 - OEIS

%I #3 Apr 09 2013 10:22:09

%S 452,2052,5584,12476,23568,41668,67136,104112,153604,219728,303468,

%T 412720,545012,709272,907828,1146704,1426212,1759348,2142176,2590236,

%U 3101848,3686444,4346808,5102188,5942936

%N Number of idempotent 4X4 0..n matrices

%C Row 4 of A222821

%e Some solutions for n=3

%e ..0..0..0..2....1..1..2..0....0..0..0..0....0..3..3..2....0..1..2..1

%e ..0..0..3..0....0..0..0..0....2..1..3..0....0..0..0..0....0..1..1..0

%e ..0..0..1..0....0..0..0..0....0..0..0..0....0..1..1..0....0..0..0..0

%e ..0..0..0..1....0..0..3..1....2..0..2..1....0..0..0..1....0..0..1..1

%K nonn

%O 1,1

%A _R. H. Hardin_ Apr 09 2013