Base 28 Repunits
Table
Format: small prime × proven prime<size> × (probable prime)<size> × [composite]<size> × {unknown}<size>
40: | \[{28^{40}-1\over27}\] | 52 × 11 × 29 × 41 × 61 × 157 × 14561 × 29201 × 41641 × 53951 × 84961 × 614657 × 637421 × 2863024493281<13> |