Base 15 Repunits
Table
Format: small prime × proven prime<size> × (probable prime)<size> × [composite]<size> × {unknown}<size>
172: | \[{15^{172}-1\over14}\] | 25 × 113 × 173 × 20641 × 39205337 × 5519984993<10> × 16112471507273<14> × 38664536016220999<17> × 3187525094785565082363106129<28> × 26656068987980386414408582952871386493955339704241<50> × 9366028893671911526733907581732070789157010459453362607093281789809<67> |