Base 21 Repunits
Table
Format: small prime × proven prime<size> × (probable prime)<size> × [composite]<size> × {unknown}<size>
| 40: | \[{21^{40}-1\over20}\] | 23 × 5 × 11 × 13 × 17 × 41 × 40841 × 97241 × 185641 × 3441241 × 920421641 × 415710882920521<15> |
Format: small prime × proven prime<size> × (probable prime)<size> × [composite]<size> × {unknown}<size>
| 40: | \[{21^{40}-1\over20}\] | 23 × 5 × 11 × 13 × 17 × 41 × 40841 × 97241 × 185641 × 3441241 × 920421641 × 415710882920521<15> |