Exact maximum periods of binary orientable sequences of orders 17 to 20

We give a reduced integer formulation for binary orientable sequences using one variable per reversal pair. Antisymmetric vertex balance and conditions at palindromic vertices characterize balanced directed realizations. Integer dual potentials, odd-cut inequalities and a parity correction yield checkable upper certificates. Complete cyclic sequences attain these bounds, establishing M17 = 63578, M18 = 128794, M19 = 257650 and M20 = 519284. The package also supplies matching witnesses and certificates for every order from five through sixteen, reproducing the known maxima. It includes the manuscript, full hexadecimal sequences, exact certificates, standard-Python checkers, computation logs and a SHA256 manifest. This work continues the preprint https://doi.org/10.5281/zenodo.23880161. Independent specialist review is pending.