Base 21 Repunits
Table
Format: small prime × proven prime<size> × (probable prime)<size> × [composite]<size> × {unknown}<size>
| * 287: | \[{21^{287}-1\over20}\] | 43 × 83 × 631 × 3319 × 14122861 × 83218931 × 17222085343<11> × 914531249431<12> × 52899783148909<14> × 3132760290771637<16> × 24463978425134922813212431<26> × [2672927547938139185660047375458262190621676840139866728396108686465549496379244496123957263926825129004446733632973229172474308969126130016819113092424669272768021596687590341791300458723847238695490116745494363797471579953962066747904507323244445504541549126550610404084660083<277>] |