Base 21 Repunits
Table
Format: small prime × proven prime<size> × (probable prime)<size> × [composite]<size> × {unknown}<size>
| * 289: | \[{21^{289}-1\over20}\] | 3469 × 44026455943<11> × 113014155161<12> × 1502097124754084594737<22> × 293921728203689009106235703<27> × [86769202443088051258905458749027253416575770945794366273520584056341731700157708631793673512680169073381587057323864902299083330399604339659327701452989284417034616618143630903813652091801635816633785689435388207907530020888365630694758088762706669244976846147735524521151062007836122336105790056418977763837<308>] |