Base 28 Repunits
Table
Format: small prime × proven prime<size> × (probable prime)<size> × [composite]<size> × {unknown}<size>
51: | \[{28^{51}-1\over27}\] | 3 × 103 × 271 × 57427 × 8061059901399457<16> × 148020807352107352204781<24> × 412037760199357579738273<24> |