Monotonic ordering of nonnegative differences 5^i-7^j, for 40>= i>=0, j>=0.

Terms

a(0) =0a(1) =4a(2) =18a(3) =24a(4) =76a(5) =118a(6) =124a(7) =282a(8) =576a(9) =618a(10) =624a(11) =724a(12) =2782a(13) =3076a(14) =3118a(15) =3124a(16) =13224a(17) =15282a(18) =15576a(19) =15618a(20) =15624a(21) =61318a(22) =75724a(23) =77782a(24) =78076a(25) =78118a(26) =78124a(27) =272976a(28) =373818a(29) =388224