Base 13 Repunits
Table
Format: small prime × proven prime<size> × (probable prime)<size> × [composite]<size> × {unknown}<size>
| 131: | \[{13^{131}-1\over12}\] | 263 × 135979 × 400852141 × 490892172446892018395299483401013733502108754948584834868805508270451316700696057763430117315431878622536780964504820752843410079<129> |