A192766 - OEIS

%I #5 Dec 18 2015 18:17:40

%S 0,0,0,17,7720,4829792,6716752296,25512182673851,280268522844817397,

%T 9139496699518220983774,891049711767000782484301987

%N Number of n X n symmetric 0..3 arrays with each element equal to at least one horizontal or vertical neighbor, containing at least one 3 and with new values 0..3 introduced in lower triangular row major order

%e Some solutions for 5X5

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

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

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

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

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

%K nonn

%O 1,4

%A _R. H. Hardin_ Jul 09 2011