Base 20 Repunits
Table
Format: small prime × proven prime<size> × (probable prime)<size> × [composite]<size> × {unknown}<size>
| * 477: | \[{20^{477}-1\over19}\] | 421 × 30529 × 51199 × 593071 × 628051 × 13217671 × 64008001 × 111566857524391<15> × 3756837362395129<16> × 24540050076369381718561<23> × 145912413086510069308789<24> × 1488281026769354544292261<25> × 8330844915605563493878201<25> × 3257272076316750353139146661697870498891<40> × 1298492579223032596001212198884047994647245663190117551588080001<64> × [1258388071864481823927204438109637209047452302379220867962126493616132125797119391772816347549479429925952639139430508668441266792911827952824585414847260183001325783603719030937805968586501843135345021817152556210545288759181010870659518500511525051905425696605051162766912725477989150217394145858054077370588002527750218899371535064326213448917344771161<355>] |