Base 21 Repunits
Table
Format: small prime × proven prime<size> × (probable prime)<size> × [composite]<size> × {unknown}<size>
| * 518: | \[{21^{518}-1\over20}\] | 2 × 11 × 43 × 631 × 3109 × 3319 × 31081 × 81867661 × 555415141 × 1681762703 × 29708087691571801<17> × 121800112688245703276562101833<30> × 255651616153989240900163414393<30> × 1098302794051275670597213771151<31> × 7995105693353508392600118377453099<34> × 379919184478057330357419845346252603881265273961<48> × [2373775227725817446741980093020720842612618929914336353772515321127169338860525882520631111534157597515872208027844662244648833847030331432052063898799451816329548471951<169>] × [3785980420959871073502317924931706811051522283950040325626067016605390783740586159730373127516202769748478565327089487688357591821310650379008828398768766182167958354647788167189981254930469348210183768379038527939923191356636499162536191728092839537006358393155974957744686621721231761<286>] |