Skolem–Mahler–Lech theorem

In algebraic number theory, the Skolem–Mahler–Lech theorem states that if a sequence of numbers satisfies a linear recurrence with constant coefficients, then with finitely many exceptions the positions at which the sequence is zero form a regularly repeating pattern. This result is named after Thoralf Skolem (who proved the theorem for sequences of rational numbers), Kurt Mahler (who proved it for sequences of algebraic numbers), and Christer Lech (who proved it for sequences with values in any field of characteristic zero.

Source: Wikipedia — Skolem–Mahler–Lech theorem (CC BY-SA 4.0)