Base 31 Repunits
Table
Format: small prime × proven prime<size> × (probable prime)<size> × [composite]<size> × {unknown}<size>
56: | \[{31^{56}-1\over30}\] | 27 × 13 × 29 × 37 × 113 × 409 × 1129 × 7253 × 11971 × 13469 × 71821 × 277739477 × 917087137 × 36004683284137<14> × 152490484148901066281<21> |