Base 7 Repunits
Table
Format: small prime × proven prime<size> × (probable prime)<size> × [composite]<size> × {unknown}<size>
66: | \[{7^{66}-1\over6}\] | 23 × 3 × 19 × 23 × 43 × 67 × 1123 × 3631 × 293459 × 1532917 × 10746341 × 12323587 × 1357105535093947<16> |