Base 15 Repunits
Table
Format: small prime × proven prime<size> × (probable prime)<size> × [composite]<size> × {unknown}<size>
56: | \[{15^{56}-1\over14}\] | 26 × 7 × 17 × 29 × 113 × 1489 × 1743463 × 10678711 × 766028506097<12> × 4454215139669<13> × 21975395880100433<17> |