Base 20 Repunits
Table
Format: small prime × proven prime<size> × (probable prime)<size> × [composite]<size> × {unknown}<size>
| 74: | \[{20^{74}-1\over19}\] | 3 × 7 × 149 × 65269 × 368447 × 2889957151 × 9609038940231949<16> × 124065005275823894023123<24> × 383493384240205993228059557962159<33> |