a(1) = 3; a(n) is smallest number >= a(n-1) such that the juxtaposition a(1)a(2)...a(n) is a prime.

Terms

a(0) =3a(1) =7a(2) =9a(3) =51a(4) =51a(5) =51a(6) =97a(7) =131a(8) =157a(9) =159a(10) =243a(11) =309a(12) =327a(13) =363a(14) =383a(15) =411a(16) =487a(17) =639a(18) =873a(19) =983a(20) =1231a(21) =1257a(22) =1337a(23) =1549a(24) =1589a(25) =2101a(26) =2159a(27) =2317a(28) =2871a(29) =2907