Base 21 Repunits
Table
Format: small prime × proven prime<size> × (probable prime)<size> × [composite]<size> × {unknown}<size>
| 279: | \[{21^{279}-1\over20}\] | 373 × 463 × 1303 × 85775383 × 4540713283<10> × 3936833990413<13> × 651628437669343<15> × 272581865551637989<18> × 1512697888680331226923639<25> × 1977047383166099579708137<25> × 5490236844314625181981860471139<31> × 7687249112242592598176964045333142849438561<43> × 5124563119985881545547614566066965859492534912423592160251967631470642615502260363198853179223749652750832718152071442779420635646690770917957673248674281809631586485551053449<175> |