Base 21 Repunits
Table
Format: small prime × proven prime<size> × (probable prime)<size> × [composite]<size> × {unknown}<size>
82: | \[{21^{82}-1\over20}\] | 2 × 11 × 83 × 1231 × 1766117 × 14122861 × 83218931 × 17222085343<11> × 914531249431<12> × 52899783148909<14> × 33985282117517881270903492784746835442538163<44> |