Order 5 Tetramagic Series Impossibility Theorem. There are no order 5 tetramagic series. Proof. S1 = 65 S2 = 1105 ≡ 7 (mod 9) S3 = 21125 ≡ 2 (mod 9) S4 = 430729 ≡ 7 (mod 9) From the Modulo 9/3 Tetramagic Series Lemma, this tetramagic series must have 7 entries of 2 (mod 3). An order 5 tetramagic series must have at least 7 entries.