Base 13 Repunits
Table
Format: small prime × proven prime<size> × (probable prime)<size> × [composite]<size> × {unknown}<size>
81: | \[{13^{81}-1\over12}\] | 34 × 61 × 650971 × 1609669 × 57583418699431<14> × 1102123844336048491<19> × 430119736863576885514326550014240994253359<42> |