Base 5 Repunits
Table
Format: small prime × proven prime<size> × (probable prime)<size> × [composite]<size> × {unknown}<size>
| 128: | \[{5^{128}-1\over4}\] | 27 × 3 × 13 × 17 × 313 × 641 × 769 × 2593 × 11489 × 29423041 × 75068993 × 241931001601<12> × 3666499598977<13> × 96132956782643741951225664001<29> |