Base 20 Repunits
Table
Format: small prime × proven prime<size> × (probable prime)<size> × [composite]<size> × {unknown}<size>
| 91: | \[{20^{91}-1\over19}\] | 29 × 71 × 3121 × 32719 × 142559 × 9690539 × 104933918101562798067516186656513621<36> × 42753079684768103157355121804168940801106384712792554767161<59> |