Composite numbers for which both sum and product of digits are primes.

Terms

a(0) =12a(1) =21a(2) =115a(3) =511a(4) =1112a(5) =1121a(6) =1211a(7) =11711a(8) =13111a(9) =17111a(10) =31111a(11) =71111a(12) =111112a(13) =121111a(14) =211111a(15) =1111115a(16) =1111117a(17) =1111171a(18) =1111511a(19) =1115111a(20) =1151111a(21) =1511111a(22) =1711111a(23) =5111111a(24) =7111111a(25) =111111115a(26) =111111151a(27) =111111311a(28) =111111511a(29) =111115111