Emirps whose products of digits are prime.

Terms

a(0) =13a(1) =17a(2) =31a(3) =71a(4) =113a(5) =311a(6) =1151a(7) =1511a(8) =111211a(9) =112111a(10) =1111711a(11) =1171111a(12) =11111117a(13) =11113111a(14) =11131111a(15) =71111111a(16) =111111131a(17) =131111111a(18) =1111115111a(19) =1115111111a(20) =11111111113a(21) =31111111111