Semiprimes for which both the sum and the product of the digits is also a semiprime.

Terms

a(0) =4a(1) =6a(2) =9a(3) =22a(4) =33a(5) =55a(6) =77a(7) =91a(8) =123a(9) =141a(10) =177a(11) =213a(12) =217a(13) =321a(14) =411a(15) =717a(16) =721a(17) =771a(18) =1135a(19) =1157a(20) =1315a(21) =1351a(22) =1513a(23) =1517a(24) =1751a(25) =3151a(26) =5131a(27) =5311a(28) =7115a(29) =11157