%I #6 Jun 11 2024 00:06:40
%S 110,6089,422538,32439684,2592092409,213854374926,17881871080466,
%T 1526776149775282
%N Number of (n+1) X (n+1) 0..3 arrays with nondecreasing min(x(i,j),x(i,j-1)) in the i direction and nondecreasing absolute value of x(i,j)-x(i-1,j) in the j direction.
%C Diagonal of A251037.
%e Some solutions for n=2
%e ..2..1..2....1..1..2....1..1..0....3..0..2....1..2..0....1..3..1....0..0..1
%e ..2..1..3....1..1..2....1..1..1....3..0..3....1..3..2....1..2..2....1..1..3
%e ..3..2..2....1..2..3....1..2..2....3..0..1....1..3..2....2..3..3....2..3..1
%Y Cf. A251037.
%K nonn
%O 1,1
%A _R. H. Hardin_, Nov 29 2014