Base 18 Repunits
Table
Format: small prime × proven prime<size> × (probable prime)<size> × [composite]<size> × {unknown}<size>
| 77: | \[{18^{77}-1\over17}\] | 23 × 199 × 449 × 463 × 16127 × 51217 × 80207 × 4226158024555207354137717207823767090063569445942721682870403141495192673<73> |