Numbers k such that for any single digit d of k the d-th semiprime sp(k) is substring of k.

Terms

a(0) =104a(1) =410a(2) =1004a(3) =1014a(4) =1040a(5) =1041a(6) =1044a(7) =1104a(8) =1410a(9) =4010a(10) =4100a(11) =4101a(12) =4104a(13) =4110a(14) =4410a(15) =10004a(16) =10014a(17) =10040a(18) =10041a(19) =10044a(20) =10104a(21) =10114a(22) =10140a(23) =10141a(24) =10144a(25) =10145a(26) =10400a(27) =10401a(28) =10404a(29) =10410