Base 21 Repunits
Table
Format: small prime × proven prime<size> × (probable prime)<size> × [composite]<size> × {unknown}<size>
| 207: | \[{21^{207}-1\over20}\] | 47 × 463 × 19597 × 85775383 × 459878292118921111<18> × 110173915920133084951<21> × 139870566115103282847737<24> × 3384589507843147005879370009<28> × 31179105887601949149105715319437017328831<41> × 9147769599005285165059853711940714465612730316340092611818747685472062074458750462990178604106947837354893313548037617430835719<127> |