Base 21 Repunits
Table
Format: small prime × proven prime<size> × (probable prime)<size> × [composite]<size> × {unknown}<size>
| 390: | \[{21^{390}-1\over20}\] | 2 × 5 × 11 × 31 × 79 × 131 × 211 × 421 × 463 × 521 × 547 × 1171 × 2551 × 9391 × 11701 × 18181 × 40841 × 185641 × 189437 × 443431 × 501001 × 629773 × 516094151 × 7021471715414521<16> × 101619538800983513441<21> × 7691526674487958994017<22> × 702978785993374112119171<24> × 80459337199345300130638393<26> × 24706699213176328849940942101<29> × 57931461377789233256346069736652710022521<41> × 47999819885150422820855221255204479443163906801765079421<56> × 331193022912357526299665829559204103846377996260934491661187550691945729808193292668193813261396861<99> × 12801249738878817126188071191894856280718343847929106839732904881739093191476709420994139418551374413291<104> |