Base 21 Repunits
Table
Format: small prime × proven prime<size> × (probable prime)<size> × [composite]<size> × {unknown}<size>
| 154: | \[{21^{154}-1\over20}\] | 2 × 112 × 23 × 43 × 631 × 3319 × 6073 × 10362529 × 81867661 × 6225803431<10> × 123679698913<12> × 17513875027111<14> × 15502260840362954719909<23> × 37681894326794146626121<23> × 312273321889143336074893<24> × 39824892937303186001525100993399811<35> × 82721492925050166710438512180782661<35> |