a(n) is the smallest prime divisor of the number obtained from concatenation of the first n primes.

Terms

a(0) =2a(1) =23a(2) =5a(3) =2357a(4) =7a(5) =23a(6) =11a(7) =7a(8) =61a(9) =3a(10) =17a(11) =7a(12) =25391a(13) =6899a(14) =1597a(15) =3a(16) =17a(17) =3a(18) =1019a(19) =3a(20) =17a(21) =211a(22) =41378209a(23) =3a(24) =479a(25) =3a(27) =3a(28) =107a(29) =3a(30) =643