Base 2 Repunits
Table
Format: small prime × proven prime<size> × (probable prime)<size> × [composite]<size> × {unknown}<size>
| 319: | \[2^{319}-1\] | 23 × 89 × 233 × 1103 × 2089 × 18503 × 64439 × 84819793631<11> × 9609322039095554268277107484843200218262250152281700954275029793<64> |