Base 21 Repunits
Table
Format: small prime × proven prime<size> × (probable prime)<size> × [composite]<size> × {unknown}<size>
111: | \[{21^{111}-1\over20}\] | 463 × 4663 × 31081 × 21475393 × 1681762703 × 7995105693353508392600118377453099<34> × 1506746820371368761835938047460405587619684925236106295173833131814373634461587418519<85> |