Base 21 Repunits
Table
Format: small prime × proven prime<size> × (probable prime)<size> × [composite]<size> × {unknown}<size>
| 172: | \[{21^{172}-1\over20}\] | 22 × 11 × 13 × 17 × 173 × 15739 × 126851 × 4818409 × 295931677 × 11665928381<11> × 169367548429<12> × 1163308526467<13> × 1229778870010013<16> × 478811691676843729951<21> × 35842614220783025524408588074144786493150233831596714503<56> × 56832351855909996916126094373146668608682666750117601137022471619056029<71> |