Base 15 Repunits
Table
Format: small prime × proven prime<size> × (probable prime)<size> × [composite]<size> × {unknown}<size>
| 71: | \[{15^{71}-1\over14}\] | 91733 × 5957753 × 272301574062887284439621057578687<33> × 152648701624697715072344529259283770507<39> |