3-almost primes with semiprime digits (digits 4, 6, 9 only).

Terms

a(0) =44a(1) =66a(2) =99a(3) =494a(4) =646a(5) =946a(6) =964a(7) =969a(8) =994a(9) =4646a(10) =4669a(11) =4949a(12) =4966a(13) =4994a(14) =4996a(15) =6446a(16) =6466a(17) =6494a(18) =6946a(19) =6964a(20) =6969a(21) =6994a(22) =9494a(23) =9499a(24) =9644a(25) =9669a(26) =9694a(27) =9699a(28) =9994a(29) =44446