Counting functions and expected values for the lattice profile at n

Recently, Dorfer and Winterhof introduced and analyzed a lattice test for sequences of length n over a finite field. We determine the number of sequences η of length n with given largest dimension Sn(η)=S for passing this test. From this result we derive an exact formula for the expected value of Sn(η). For the binary case we characterize the (infinite) sequences η with maximal possible Sn(η) for all n.