Ruzsa’s genus-one problem

Found by a dedicated fixed-cardinality search at modulus 703. Starting from witness #111, residue 328 was the least-conflicting possible 17th element (seven ordered nontrivial solutions). A tabu search that evaluated every one-residue swap crossed the local barriers and found this set after 10,631 iterations. Direct enumeration gives exactly 17 solutions to a+3b=2c+2d, all diagonal.