Base 7 Repunits
Table
Format: small prime × proven prime<size> × (probable prime)<size> × [composite]<size> × {unknown}<size>
| 131: | \[{7^{131}-1\over6}\] | 85053461164796801949539541639542805770666392330682673302530819774105141531698707146930307290253537320447270457<110> |