Base 21 Repunits
Table
Format: small prime × proven prime<size> × (probable prime)<size> × [composite]<size> × {unknown}<size>
| 217: | \[{21^{217}-1\over20}\] | 43 × 631 × 3319 × 3907 × 11719 × 4540713283<10> × 3936833990413<13> × 1327673263118497<16> × 272581865551637989<18> × 1844299007032373076846655934009031991<37> × 84845193781010150935676027148732557958347095338405197115142184728787472503865504557463709634588421811120100878117230159549154644555211644083836856335834777364695510001743187985811<179> |