Base 21 Repunits
Table
Format: small prime × proven prime<size> × (probable prime)<size> × [composite]<size> × {unknown}<size>
| 30: | \[{21^{30}-1\over20}\] | 2 × 5 × 11 × 31 × 211 × 421 × 463 × 2551 × 9391 × 18181 × 40841 × 185641 × 501001 |
Format: small prime × proven prime<size> × (probable prime)<size> × [composite]<size> × {unknown}<size>
| 30: | \[{21^{30}-1\over20}\] | 2 × 5 × 11 × 31 × 211 × 421 × 463 × 2551 × 9391 × 18181 × 40841 × 185641 × 501001 |