Base 21 Repunits
Table
Format: small prime × proven prime<size> × (probable prime)<size> × [composite]<size> × {unknown}<size>
| * 253: | \[{21^{253}-1\over20}\] | 47 × 4049 × 19597 × 13001671 × 17513875027111<14> × 45398137923491<14> × 139870566115103282847737<24> × 716469520114103148965309<24> × [430004335092778819680601670783343794639985673679213525706766144975995594034235822630411382954225228737383356734423861753870520024265553019853571796263863054112216613749437368374905648619843413195643691582542514099860353481505115422412783562201<243>] |