Base 15 Repunits
Table
Format: small prime × proven prime<size> × (probable prime)<size> × [composite]<size> × {unknown}<size>
51: | \[{15^{51}-1\over14}\] | 103 × 241 × 1123 × 1022449 × 3496561 × 1045002649 × 6734509609<10> × 97406069823939953821<20> |