The next six numbers are
2 3 0 3 2 3
Now the starting point element/vector is
A = [0 1 2 1 0 1 0 3 0 1 0 3 2 1 2 3 2 3 0 3 2 3];
(note that if A1=A(1:11) and A2 = A(12:22), then A1 + A2 = 3 * ones(1,11))
If we start with A3 = A, then we have a recursive formula An=[A(n-1) 3-A(n-1)]
Credit: Roman Dyba, Mountain View CA