Base 4 Repunits
Table
Format: small prime × proven prime<size> × (probable prime)<size> × [composite]<size> × {unknown}<size>
| 409: | \[{4^{409}-1\over3}\] | 4480666067023<13> × 76025626689833<14> × 176596029450915408652219208387<30> × 18791937710720575305760721588966789412396307<44> × 132798898521004777680398175782876221227618319985219<51> × 3881196575913244673719425770871246487895686937951690944453838586764072695131586617955811936945129<97> |