Composite and every divisor (except 1) contains the digit 4.

Terms

a(0) =1849a(1) =6407a(2) =14227a(3) =14309a(4) =14921a(5) =16403a(6) =16441a(7) =17243a(8) =18409a(9) =18847a(10) =19049a(11) =19147a(12) =20459a(13) =20941a(14) =21457a(15) =21479a(16) =21949a(17) =22427a(18) =23453a(19) =25427a(20) =27649a(21) =30409a(22) =30463a(23) =31949a(24) =34921a(25) =40463a(26) =40721a(27) =43009a(28) =44227a(29) =44509