Base 20 Repunits
Table
Format: small prime × proven prime<size> × (probable prime)<size> × [composite]<size> × {unknown}<size>
| 207: | \[{20^{207}-1\over19}\] | 139 × 421 × 691 × 1381 × 509221 × 64008001 × 119553964489<12> × 113317059163579<15> × 4892995476168664219561<22> × 46266279097921483078651<23> × 887612944642122132741202450909<30> × 2184862032570422308074444966133284250690548357572266405681628366683042273433433463998738991787340358680001832686449969881551801182126914937648421<145> |