Base 21 Repunits
Table
Format: small prime × proven prime<size> × (probable prime)<size> × [composite]<size> × {unknown}<size>
| 135: | \[{21^{135}-1\over20}\] | 5 × 109 × 163 × 211 × 463 × 9391 × 18181 × 40841 × 4779433 × 41489011 × 57815101 × 85775383 × 7429452749713<13> × 192787782171121<15> × 22554946693833031<17> × 2447244788249267691839821<25> × 335762586163588511737475534667790066590701118595773133381<57> |