%I #5 Mar 31 2012 12:37:33

%S 7,1316,1596154,11066406572,437975212393770,98959148496365005996,

%T 127648944977287507883659858,940014634186299364055616416384316

%N Number of (n+1)X(n+1) 0..3 arrays with every 2X2 subblock having one or three distinct values, and new values 0..3 introduced in row major order

%C Diagonal of A210404

%e Some solutions for n=4

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

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

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

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

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

%K nonn

%O 1,1

%A _R. H. Hardin_ Mar 21 2012