{e^n}-th prime, where {e^n} is closest integer to e^n, A000227.

Terms

a(0) =2a(1) =5a(2) =17a(3) =71a(4) =257a(5) =857a(6) =2767a(7) =8807a(8) =27239a(9) =82939a(10) =249779a(11) =744949a(12) =2201281a(13) =6463081a(14) =18858529a(15) =54764947a(16) =158330587a(17) =456016949a(18) =1309050653a(19) =3746543951a(20) =10694444393a(21) =30453898201a(22) =86534078387a(23) =245401348403a(24) =694683409451