a(1) = 6; a(n) is smallest number >= a(n-1) such that the juxtaposition a(1)a(2)...a(n) is a prime.

Terms

a(0) =6a(1) =7a(2) =7a(3) =9a(4) =27a(5) =59a(6) =69a(7) =181a(8) =201a(9) =257a(10) =267a(11) =399a(12) =573a(13) =603a(14) =861a(15) =901a(16) =923a(17) =1021a(18) =1133a(19) =1239a(20) =1251a(21) =1519a(22) =1589a(23) =1729a(24) =1863a(25) =1901a(26) =2541a(27) =3001a(28) =3017a(29) =3049