Base 8 Repunits
Table
Format: small prime × proven prime<size> × (probable prime)<size> × [composite]<size> × {unknown}<size>
| 137: | \[{8^{137}-1\over7}\] | 823 × 27261904199932321<17> × 32032215596496435569<20> × 5439042183600204290159<22> × 647923469936355993348337<24> × 298291609560028759691116319707152042481<39> |