Base 7 Repunits
Table
Format: small prime × proven prime<size> × (probable prime)<size> × [composite]<size> × {unknown}<size>
| 208: | \[{7^{208}-1\over6}\] | 26 × 52 × 17 × 53 × 157 × 313 × 1201 × 169553 × 85094881 × 228511817 × 16148168401<11> × 1195857367853217109<19> × 17712988461899423081645348353<29> × 1377454635342537460935008154217<31> × 76053626281572299980201419323699150165495621951615617<53> |