Base 16 Repunits
Table
Format: small prime × proven prime<size> × (probable prime)<size> × [composite]<size> × {unknown}<size>
| 39: | \[{16^{39}-1\over15}\] | 3 × 7 × 132 × 53 × 79 × 157 × 313 × 1249 × 1613 × 2731 × 3121 × 8191 × 21841 × 121369 × 22366891 |