Base 2 Repunits
Table
Format: small prime × proven prime<size> × (probable prime)<size> × [composite]<size> × {unknown}<size>
| 253: | \[2^{253}-1\] | 232 × 47 × 89 × 178481 × 4103188409 × 199957736328435366769577<24> × 44667711762797798403039426178361<32> |