Base 18 Repunits
Table
Format: small prime × proven prime<size> × (probable prime)<size> × [composite]<size> × {unknown}<size>
| 56: | \[{18^{56}-1\over17}\] | 52 × 13 × 19 × 29 × 113 × 449 × 929 × 1373 × 3697 × 17837 × 80207 × 1623833 × 32222107 × 361981632928757554946658433<27> |