%I #4 Jun 30 2012 11:56:17

%S 6327,120133,604639,3510112,9131098,29365738,56599992,127113628,

%T 255379242,499365458,784233528,1531915046,2261261860,3473439982,

%U 5267581848,8552671195,11581885709,17881607889,23603815011,34808081571

%N Number of 4X4 0..n matrices whose square is also a 0..n matrix

%C Row 4 of A213990

%H R. H. Hardin, <a href="/A213993/b213993.txt">Table of n, a(n) for n = 1..40</a>

%e Some solutions for n=3

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

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

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

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

%K nonn

%O 1,1

%A _R. H. Hardin_ Jun 30 2012