A210930 - OEIS

A210930

Number of n X n 0..3 symmetric matrices with every element equal to one or two horizontal and vertical neighbors, and new values 0..3 introduced in lower triangle row major order

%I #5 Dec 18 2015 18:18:06

%S 0,1,2,64,4730,1354791,943637970,1907539841676,10349004212065264,

%T 156102455896727660205

%N Number of n X n 0..3 symmetric matrices with every element equal to one or two horizontal and vertical neighbors, and new values 0..3 introduced in lower triangle row major order

%e Some solutions for n=4

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

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

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

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

%K nonn

%O 1,3

%A _R. H. Hardin_ Mar 29 2012