Base 21 Repunits
Table
Format: small prime × proven prime<size> × (probable prime)<size> × [composite]<size> × {unknown}<size>
123: | \[{21^{123}-1\over20}\] | 83 × 463 × 14122861 × 83218931 × 17222085343<11> × 914531249431<12> × 52899783148909<14> × 1474011104949958983856849<25> × 367541000424902470501250402608394113<36> × 10534031885860928959842755452634273061203152273<47> |