Number of distinct primes embedded in prime(n) as substrings.

Terms

a(0) =1a(1) =1a(2) =1a(3) =1a(4) =1a(5) =2a(6) =2a(7) =1a(8) =3a(9) =2a(10) =2a(11) =3a(12) =1a(13) =2a(14) =2a(15) =3a(16) =2a(17) =1a(18) =2a(19) =2a(20) =3a(21) =2a(22) =2a(23) =1a(24) =2a(25) =1a(26) =2a(27) =2a(28) =1a(29) =4