Base 21 Repunits
Table
Format: small prime × proven prime<size> × (probable prime)<size> × [composite]<size> × {unknown}<size>
| 180: | \[{21^{180}-1\over20}\] | 22 × 5 × 11 × 13 × 17 × 19 × 31 × 37 × 41 × 61 × 181 × 199 × 211 × 421 × 463 × 613 × 1693 × 2551 × 3181 × 9391 × 18181 × 40841 × 185641 × 501001 × 658261 × 1360861 × 41489011 × 57815101 × 85775383 × 920421641 × 4344847859197<13> × 1053606939618901<16> × 22554946693833031<17> × 41764164884102175841<20> × 82207575664095002495707981<26> × 387296681442215139403864858966948878324061<42> |