Base 28 Repunits
Table
Format: small prime × proven prime<size> × (probable prime)<size> × [composite]<size> × {unknown}<size>
55: | \[{28^{55}-1\over27}\] | 637421 × 6077039 × 50545507 × 16071033331<11> × 829366011211<12> × 94275090945167441<17> × 5906633396655970661<19> |