%I #5 Dec 18 2015 18:18:06
%S 1,3,39,2212,314852,110451021,95121973827,200885189935045,
%T 1039262747697700932,13162671799070468638683
%N Number of n X n 0..3 symmetric matrices with every element equal to zero, two or three horizontal and vertical neighbors, and new values 0..3 introduced in lower triangle row major order
%e Some solutions for n=4
%e ..0..1..2..3....0..1..2..3....0..1..0..1....0..1..0..3....0..1..2..1
%e ..1..0..1..2....1..0..1..0....1..2..1..3....1..0..2..1....1..2..3..0
%e ..2..1..3..3....2..1..0..2....0..1..2..1....0..2..1..3....2..3..2..3
%e ..3..2..3..3....3..0..2..1....1..3..1..2....3..1..3..0....1..0..3..1
%K nonn
%O 1,2
%A _R. H. Hardin_ Mar 29 2012
|