Pset3 problem2 have incorrect setting

[qlibp]

Origin:
example (a : ℕ → ℝ) (ha : ∀ n, a n = (n + 1) / n) : ∃ L, SeqLim a L := by

To Be:
example (a : ℕ → ℝ) (ha : ∀ n > 0, a n = (n + 1) / n) : ∃ L, SeqLim a L := by

Otherwise, a n is not well-defined at n=0