To represent a choice of one out of 61 possibilities, you will likely need at least 6 integer variables. A single variable with range 0..61 is unlikely to produce an MILP formulation.
-- Michael henne...@mail.cs.ndsu.nodak.edu "His longhand was fairly good in his youth, but as he got older it got smaller, more scribbly, and harder to read; although, like being hanged, one can get used to it." -- Gordon Dickson on H.P. Lovecraft's handwriting
