The 2^n-th irregular prime.

Terms

a(0) =37a(1) =59a(2) =101a(3) =157a(4) =311a(5) =557a(6) =971a(7) =2111a(8) =4909a(9) =10457a(10) =23099a(11) =50359a(12) =109589a(13) =235577a(14) =506281a(15) =1065013a(16) =2249609a(17) =4745963a(18) =10010393a(19) =21030973a(20) =44070017a(21) =92079881a(22) =192011803a(23) =399771653a(24) =830692727a(25) =1724024177