Base 21 Repunits
Table
Format: small prime × proven prime<size> × (probable prime)<size> × [composite]<size> × {unknown}<size>
| 240: | \[{21^{240}-1\over20}\] | 24 × 5 × 11 × 13 × 17 × 31 × 41 × 61 × 73 × 193 × 211 × 241 × 421 × 433 × 463 × 601 × 673 × 2551 × 3121 × 3181 × 3361 × 7681 × 9391 × 9521 × 18181 × 40841 × 62897 × 97241 × 185641 × 300673 × 501001 × 1001713 × 1360861 × 3441241 × 12426241 × 22995281 × 25392481 × 33534961 × 40086001 × 518118697 × 920421641 × 3184193681 × 363230092241<12> × 415710882920521<15> × 1053606939618901<16> × 84947863319467630678021906123321<32> × 303793280233949747866746506198881<33> × 13770093248814600891037861709841361<35> |