Base 15 Repunits
Table
Format: small prime × proven prime<size> × (probable prime)<size> × [composite]<size> × {unknown}<size>
| 79: | \[{15^{79}-1\over14}\] | 317 × 289141 × 635202924304143926394929553206270861232915983823448379207983060226587253234146827953<84> |