Base 5 Repunits
Table
Format: small prime × proven prime<size> × (probable prime)<size> × [composite]<size> × {unknown}<size>
| 121: | \[{5^{121}-1\over4}\] | 12101 × 486179 × 12207031 × 13094322377956920597215509541997540493466263550896158313340716530769<68> |