Base 15 Repunits
Table
Format: small prime × proven prime<size> × (probable prime)<size> × [composite]<size> × {unknown}<size>
78: | \[{15^{78}-1\over14}\] | 24 × 53 × 79 × 211 × 241 × 1249 × 20749 × 157483 × 5557501 × 16655159 × 1539711288259<13> × 606451512892729597861<21> × 3230061048592350229141<22> |