Base 20 Repunits
Table
Format: small prime × proven prime<size> × (probable prime)<size> × [composite]<size> × {unknown}<size>
65: | \[{20^{65}-1\over19}\] | 11 × 61 × 131 × 251 × 521 × 3121 × 3511 × 4421 × 90481 × 142559 × 9690539 × 4470064171<10> × 144142570154831<15> × 4329520082233745656921<22> |