a(n+1) = gpf(2*prime(a(n-1)) + prime(a(n))) where gpf = greatest prime factor, with a(0)=1, a(1)=2.

Terms

a(0) =1a(1) =2a(2) =7a(3) =23a(4) =13a(5) =23a(6) =11a(7) =197a(8) =421a(9) =113a(10) =13a(11) =17a(12) =47a(13) =47a(14) =211a(15) =191a(16) =1249a(17) =499a(18) =1039a(19) =79a(20) =97a(21) =23a(22) =367a(23) =881a(24) =337a(25) =409a(26) =2447a(27) =277a(28) =857a(29) =487