Base 21 Repunits
Table
Format: small prime × proven prime<size> × (probable prime)<size> × [composite]<size> × {unknown}<size>
| 220: | \[{21^{220}-1\over20}\] | 22 × 5 × 112 × 13 × 17 × 23 × 41 × 89 × 661 × 881 × 2971 × 6073 × 39161 × 40841 × 185641 × 10362529 × 920421641 × 5664205361<10> × 2599537710221<13> × 17513875027111<14> × 9036610069262821<16> × 270573999780463721<18> × 8407123807237422961<19> × 4718573764413203147069<22> × 54598616218616435702441<23> × 140065954810191667464461<24> × 427340685127009875562001<24> × 109059874229221664821286941<27> × 3246571517440758538481384401171<31> |