Base 18 Repunits
Table
Format: small prime × proven prime<size> × (probable prime)<size> × [composite]<size> × {unknown}<size>
86: | \[{18^{86}-1\over17}\] | 19 × 431 × 5129762401<10> × 597455435179<12> × 4464951753212028068412713<25> × 28971751902509263440682681<26> × 16276512351314787405765413256433<32> |