Ok, here is a way:
A=[1,0,0,1,1,1];
% turn A into a 1x6 string array
tmp=string(A);
% reshape into a 3xN string array, then transpose to Nx3
tmp=reshape(tmp,3,[])';
% combine each row, leaving a Nx1 string array
tmp=join(tmp,'');
% convert back to a Nx1 numeric array, then transpose to 1xN
B = double(tmp)';
or, in one line:
B = double(join(reshape(string(A),3,[])',''))'
