Composite numbers whose prime factors contain no digits other than 5 and 9.

Terms

a(0) =25a(1) =125a(2) =295a(3) =625a(4) =1475a(5) =2995a(6) =3125a(7) =3481a(8) =7375a(9) =14975a(10) =15625a(11) =17405a(12) =35341a(13) =36875a(14) =74875a(15) =78125a(16) =87025a(17) =176705a(18) =184375a(19) =205379a(20) =299995a(21) =358801a(22) =374375a(23) =390625a(24) =435125a(25) =479795a(26) =497795a(27) =883525a(28) =921875a(29) =1026895