a(1) = 9; a(n) is smallest number >= a(n-1) such that the juxtaposition a(1)a(2)...a(n) is a prime.

Terms

a(0) =9a(1) =11a(2) =21a(3) =21a(4) =23a(5) =33a(6) =37a(7) =93a(8) =119a(9) =129a(10) =133a(11) =147a(12) =293a(13) =321a(14) =429a(15) =433a(16) =497a(17) =627a(18) =661a(19) =897a(20) =1161a(21) =1187a(22) =1197a(23) =1711a(24) =1769a(25) =1807a(26) =2097a(27) =2099a(28) =4143a(29) =4149