Base 20 Repunits
Table
Format: small prime × proven prime<size> × (probable prime)<size> × [composite]<size> × {unknown}<size>
| 212: | \[{20^{212}-1\over19}\] | 3 × 7 × 107 × 401 × 593071 × 1588729 × 18429161 × 24540050076369381718561<23> × 14513538368939816484160568138201567453<38> × 3257272076316750353139146661697870498891<40> × 400854439463328526924788607031597685803293279928793947485536270583<66> × 4761090921768007090153183431468339190769693062389826606707636565206236304146662153093<85> |