Base 20 Repunits
Table
Format: small prime × proven prime<size> × (probable prime)<size> × [composite]<size> × {unknown}<size>
| 52: | \[{20^{52}-1\over19}\] | 3 × 7 × 53 × 401 × 2081 × 2549 × 3121 × 142559 × 502321 × 9690539 × 735408649 × 628605693732325702045277<24> |