Base 2 Repunits
Table
Format: small prime × proven prime<size> × (probable prime)<size> × [composite]<size> × {unknown}<size>
509: | \[2^{509}-1\] | 12619129 × 19089479845124902223<20> × 647125715643884876759057<24> × 10751168288022146026259956092344345159681167846281852853736470411971627982051345994439553634116438524169<104> |