Base 31 Repunits
Table
Format: small prime × proven prime<size> × (probable prime)<size> × [composite]<size> × {unknown}<size>
57: | \[{31^{57}-1\over30}\] | 3 × 331 × 571 × 7639 × 14251 × 36068660903683<14> × 88770666332610762169<20> × 1716439847900062900800798410166938893<37> |