A nonsense sequence (not well-defined).

Terms

a(0) =2a(1) =3a(2) =7a(3) =11a(4) =13a(5) =17a(6) =19a(7) =23a(8) =37a(9) =41a(10) =59a(11) =73a(12) =101a(13) =137a(14) =157a(15) =239a(16) =257a(17) =271a(18) =547a(19) =2153a(20) =2251a(21) =4649a(22) =7309a(23) =9091a(24) =19697a(25) =21683a(26) =94331a(27) =333667a(28) =928163a(29) =3324301