Base 7 Repunits
Table
Format: small prime × proven prime<size> × (probable prime)<size> × [composite]<size> × {unknown}<size>
| 155: | \[{7^{155}-1\over6}\] | 311 × 2801 × 21143 × 21391 × 21701 × 1622982371 × 9254997611<10> × 3999088279399464409<19> × 31728015189946773062954921268435825250349092899077924422648569887851893731<74> |