Base 7 Repunits
Table
Format: small prime × proven prime<size> × (probable prime)<size> × [composite]<size> × {unknown}<size>
| 137: | \[{7^{137}-1\over6}\] | 2741 × 213721 × 251533 × 57162922399254002352124124899<29> × 65480203458464902965944539043<29> × 18142811321510255442702751468712154533804561<44> |