Base 20 Repunits
Table
Format: small prime × proven prime<size> × (probable prime)<size> × [composite]<size> × {unknown}<size>
87: | \[{20^{87}-1\over19}\] | 59 × 349 × 421 × 929 × 8179 × 10789 × 143609 × 564979 × 1177459 × 466307299 × 71353204641689<14> × 3605403851353821123741083595382953185544609831777342451<55> |