Base 21 Repunits
Table
Format: small prime × proven prime<size> × (probable prime)<size> × [composite]<size> × {unknown}<size>
| 218: | \[{21^{218}-1\over20}\] | 2 × 11 × 252649631352967<15> × 243559381356675673<18> × 12437625258656743104073625051<29> × 15547495436546185942695879543470800471<38> × 311230778906803012635032244112217936159403426704742287611438860807922580555261<78> × 1075844735830122358017703049625189977667287013021268821502115973717283800539785976074877960131456456976157869419<112> |