Base 28 Repunits
Table
Format: small prime × proven prime<size> × (probable prime)<size> × [composite]<size> × {unknown}<size>
| 131: | \[{28^{131}-1\over27}\] | 787 × 9433 × 56897145979336067<17> × 24538826471975158928090069<26> × 13513551563645043981971054213977108126279091911541498002142712681928242888989514454611697417349390558232193761593547803870954834523196741481<140> |