Happy primes of the form a*10^k + b with single-digit a and b, a > 0, k > 0.

Terms

a(0) =13a(1) =19a(2) =23a(3) =31a(4) =79a(5) =97a(6) =103a(7) =109a(8) =409a(9) =709a(10) =907a(11) =1009a(12) =2003a(13) =3001a(14) =9001a(15) =9007a(16) =10009a(17) =40009a(18) =70009a(19) =90001a(20) =90007a(21) =100003a(22) =200003a(23) =400009a(24) =900001a(25) =900007a(26) =1000003a(27) =2000003a(28) =7000009a(29) =20000003