Base 20 Repunits
Table
Format: small prime × proven prime<size> × (probable prime)<size> × [composite]<size> × {unknown}<size>
| 117: | \[{20^{117}-1\over19}\] | 79 × 421 × 1171 × 3121 × 142559 × 363871 × 9690539 × 64008001 × 172311318287603732461390609<27> × 50676846610970769808122928009<29> × 256063908633871845537541706060016525021086384110684477035559<60> |