Numbers with digital product = 4.

Terms

a(0) =4a(1) =14a(2) =22a(3) =41a(4) =114a(5) =122a(6) =141a(7) =212a(8) =221a(9) =411a(10) =1114a(11) =1122a(12) =1141a(13) =1212a(14) =1221a(15) =1411a(16) =2112a(17) =2121a(18) =2211a(19) =4111a(20) =11114a(21) =11122a(22) =11141a(23) =11212a(24) =11221a(25) =11411a(26) =12112a(27) =12121a(28) =12211a(29) =14111