Base 2 Repunits
Table
Format: small prime × proven prime<size> × (probable prime)<size> × [composite]<size> × {unknown}<size>
| 299: | \[2^{299}-1\] | 47 × 599 × 8191 × 178481 × 9341359 × 14718679249<11> × 13444476836590589479<20> × 51441563151591093599<20> × 260242449712509916159<21> |