Erroneous version of A001606.

Terms

a(0) =2a(1) =4a(2) =5a(3) =7a(4) =8a(5) =11a(6) =13a(7) =16a(8) =17a(9) =19a(10) =37a(11) =41a(12) =47a(13) =53a(14) =61a(15) =71a(16) =79a(17) =113a(18) =313a(19) =353