Base 21 Repunits
Table
Format: small prime × proven prime<size> × (probable prime)<size> × [composite]<size> × {unknown}<size>
| 270: | \[{21^{270}-1\over20}\] | 2 × 5 × 11 × 19 × 31 × 37 × 109 × 163 × 199 × 211 × 271 × 421 × 463 × 541 × 613 × 2551 × 5077 × 9391 × 17497 × 18181 × 40841 × 185641 × 501001 × 658261 × 4779433 × 41489011 × 57815101 × 85775383 × 7429452749713<13> × 192787782171121<15> × 7101932659132249<16> × 22554946693833031<17> × 2447244788249267691839821<25> × 82207575664095002495707981<26> × 2810321698513575079231344181<28> × 335762586163588511737475534667790066590701118595773133381<57> × 384473692135100574059360415883054799029026247559713850344212031<63> |