Base 21 Repunits
Table
Format: small prime × proven prime<size> × (probable prime)<size> × [composite]<size> × {unknown}<size>
| 239: | \[{21^{239}-1\over20}\] | 479 × 297317 × 4322592575557<13> × 21310629067523<14> × 39037825398329980533479789832898396398066454933146690954674407945419478600703813297698466584563372409691833017412005057615988657295366964885447859450068793754469327159629675857635193529895761087323529081475871855894860471813250930390936561568700582036345620552684462204297954846183<281> |