odds static method

List<int> odds(
  1. int columns
)

Implementation

static List<int> odds(int columns) => columns > 1 ? List.generate(columns, (c){
  if(c == 0 || c == columns - 1) return c + 1;
  return (c + 1) % 2 == 0 ? -1 : c + 1;
}).where((i)=>i != -1).toList() : [1];