Base 4 Repunits
Table
Format: small prime × proven prime<size> × (probable prime)<size> × [composite]<size> × {unknown}<size>
| 207: | \[{4^{207}-1\over3}\] | 32 × 7 × 19 × 47 × 73 × 139 × 79903 × 178481 × 2796203 × 634569679 × 168749965921<12> × 2232578641663<13> × 10052678938039<14> × 42166482463639<14> × 6113142872404227834840443898241613032969<40> |