Base 21 Repunits
Table
Format: small prime × proven prime<size> × (probable prime)<size> × [composite]<size> × {unknown}<size>
| 380: | \[{21^{380}-1\over20}\] | 22 × 5 × 11 × 13 × 17 × 41 × 191 × 229 × 457 × 761 × 1901 × 40841 × 185641 × 205391 × 609673 × 860631601 × 920421641 × 4307457701<10> × 12061389013<11> × 18806124191<11> × 19449969211<11> × 54921106624003<14> × 619598441951897251<18> × 987749814642143197<18> × 2522688573446019221<19> × 3794540985952206860593938878074866571399837<43> × 4962575794097659196896553056277931780683391554141<49> × 224946077318312621202864321882925242281698103188770132390249098696465091061151<78> × 4689829325018533702879795987151172295424804753362048204926853696291245921746767391833232021685308610594287103019961752101953208732388127467956366106813111750942961081<166> |