Order 35 Hexamagic Series Impossibility Theorem. There are no order 35 hexamagic series. Proof. S1 = 1455 S2 = 17528735 ≡ 2 (mod 9) S3 = 16111095875 ≡ 8 (mod 9) S4 = 15795314890103 ≡ 2 (mod 9) S5 = 16130960856213875 S6 = 16944416526780308855 From the Modulo 9/3 Tetramagic Series Lemma, this hexamagic series must have 9a+6 entries of 2 (mod 3), 9b+5 entries of 1 (mod 3), and 9c+6 entries of 0 (mod 3), where a+b+c = 2. Let 3Aj+1, j=1..9(a+b)+11, be the squares of entries that are 1 or 2 (mod 3). Let 9Bj, j=1..9c+6, be the squares of entries that are 0 (mod 3). Let Tn = sum (Aj)n, j=1..9(a+b)+11, n=1,2,3. Let Un = sum (Bj)n, j=1..9c+6, n=1,2,3. S2 = 3T1 + 9(a+b)+11 + 9U1 S6 = 27T3 + 27T2 + 9T1 + 9(a+b)+11 + 729U3 (S2 - 11)/3 = T1 + 3U1 + 3(a+b) = 5842908 ≡ 0 (mod 3) thus T1 ≡ 0 (mod 3). (S6 - 11)/9 = 3T3 + 3T2 + T1 + 81U3 + (a+b) = 1882712947420034316 ≡ 0 (mod 3) thus (a+b) ≡ 0 (mod 3). Since a+b <= 2, a = 0 and b = 0. An order 35 hexamagic series must consist of 6 entries of 2 (mod 3), 5 entries of 1 (mod 3), and 24 entries of 0 (mod 3).
Starting over ... Let 3Aj+2 be an entry of 2 (mod 3), j=1..6. Let 3Bj+1 be an entry of 1 (mod 3), j=1..5. Let 3Cj be an entry of 0 (mod 3), j=1..24. Let Tn = sum (Aj)n, j=1..6, n=1..6. Let Un = sum (Bj)n, j=1..5, n=1..6. Let Vn = sum (Cj)n, j=1..24, n=1..6. S3 = (27T3 + 54T2 + 36T1 + 48) + (27U3 + 27U2 + 9U1 + 5) + 27V3 S4 = (81T4 + 4x27x2T3 + 6x9x4T2 + 4x3x8T1 + 96) + (81U4 + 4x27U3 + 6x9U2 + 4x3U1 + 5) + 81V4 S5 = (243T5 + 5x81x2T4 + 10x27x4T3 + 10x9x8T2 + 5x3x16T1 + 192) + (243U5 + 5x81U4 + 10x27U3 + 10x9U2 + 5x3U1 + 5) + 243V5 (S3 - 53)/9 = 3T3 + 6T2 + 4T1 + 3U3 + 3U2 + U1 + 3V3 = 1790121758 ≡ 2 (mod 3) thus T1 + U1 ≡ 2 (mod 3). (S4 - 101)/3 = 27T4 + 4x9x2T3 + 6x3x4T2 + 4x8T1 + 27U4 + 4x9U3 + 6x3U2 + 4U1 + 27V4 = 5265104963334 ≡ 0 (mod 3) thus 2T1 + U1 ≡ 0 (mod 3) and T1 ≡ 1 (mod 3), U1 ≡ 1 (mod 3). (S5 - 197)/3 = 81T5 + 5x27x2T4 + 10x9x4T3 + 10x3x8T2 + 5x16T1 + 81U5 + 5x27U4 + 10x9U3 + 10x3U2 + 5U1 + 81V5 = 5376986952071226 ≡ 0 (mod 3) thus 2T1 + 2U1 ≡ 0 (mod 3), which is inconsistent with T1 ≡ 1, U1 ≡ 1 (mod 3).