A213984 - OEIS

%I #5 Dec 18 2015 18:18:12

%S 2,24,1003,120133,35799856,24651985100

%N Number of n X n 0..2 matrices whose square is also a 0..2 matrix

%C Column 2 of A213990

%e Some solutions for n=3

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

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

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

%K nonn

%O 1,1

%A _R. H. Hardin_ Jun 30 2012