▁long ▁and ▁is ▁only ▁the ▁second ▁General ized ▁F erm at ▁prime ▁found ▁for ▁. ▁It ▁ranks ▁as ▁the ▁ 1 3 th ▁largest ▁known ▁prime ▁overall . ▁ ▁R ies el ▁Problem ▁, ▁Prime Grid ▁has ▁elimin ated ▁ 1 5 ▁values ▁of ▁k ▁from ▁the ▁R ies el ▁problem ▁and ▁is ▁continu ing ▁the ▁search ▁to ▁eliminate ▁the ▁ 4 9 ▁remaining ▁numbers . ▁ ▁T win ▁prime ▁search ▁Prim eg rid ▁worked ▁with ▁the ▁T win ▁Prime ▁Search ▁to ▁search ▁for ▁a ▁record - s ized ▁tw in ▁prime ▁at ▁approximately ▁ 5 8 , 7 0 0 ▁digits . ▁The ▁new ▁world ' s ▁largest ▁known ▁tw in ▁prime ▁ ▁was ▁eventually ▁discovered ▁on ▁January ▁ 1 5 , ▁ 2 0 0 7 ▁( s ieved ▁by ▁T win ▁Prime ▁Search ▁and ▁tested ▁by ▁Prime Grid ). ▁The ▁search ▁continued ▁for ▁another ▁record ▁tw in ▁prime ▁at ▁just ▁above ▁ 1 0 0 , 0 0 0 ▁digits . ▁It ▁was ▁completed ▁in ▁August ▁ 2 0 0 9 ▁when ▁Prim eg rid ▁found ▁. ▁Cont in ued ▁testing ▁for ▁tw in ▁pr imes ▁in ▁conj unction ▁with ▁the ▁search ▁for ▁a ▁Soph ie ▁Germ ain ▁prime ▁yield ed ▁a ▁new ▁record ▁tw in ▁prime ▁on ▁September ▁ 2 0 1 6 ▁upon ▁finding ▁the ▁number ▁ ▁composed ▁of ▁ 3 8 8 , 3 4 2 ▁digits . ▁ ▁Wood all ▁prime ▁search ▁, ▁the ▁project ▁has ▁discovered ▁the ▁three ▁largest ▁Wood all ▁pr imes ▁known ▁to