Monotonic ordering of nonnegative differences 4^i-5^j, for 40>= i>=0, j>=0.

Terms

a(0) =0a(1) =3a(2) =11a(3) =15a(4) =39a(5) =59a(6) =63a(7) =131a(8) =231a(9) =251a(10) =255a(11) =399a(12) =759a(13) =899a(14) =971a(15) =999a(16) =1019a(17) =1023a(18) =3471a(19) =3971a(20) =4071a(21) =4091a(22) =4095a(23) =13259a(24) =15759a(25) =16259a(26) =16359a(27) =16379a(28) =16383a(29) =49911