Base 4 Repunits
Table
Format: small prime × proven prime<size> × (probable prime)<size> × [composite]<size> × {unknown}<size>
| 133: | \[{4^{133}-1\over3}\] | 43 × 127 × 4523 × 174763 × 524287 × 106788290443848295284382097033<30> × 163537220852725398851434325720959<33> |