Base 13 Repunits
Table
Format: small prime × proven prime<size> × (probable prime)<size> × [composite]<size> × {unknown}<size>
| 68: | \[{13^{68}-1\over12}\] | 22 × 5 × 7 × 172 × 103 × 443 × 1021 × 897329 × 61165661 × 75094577 × 6152936617<10> × 15798461357509<14> × 617886851384381281<18> |