function luckyNumbers(opts={}) {
  

  opts.even =  opts.even || false;
  if (typeof opts.through == 'number') opts.through = [0, opts.through];
  let out = [],
      x = opts.even ? 2 : 1,
      max = opts.range ? opts.range[1] * 3
        : opts.through ? opts.through[1] * 12
        : opts.nth ? opts.nth * 15
        : 2000;

  for (x; x <= max; x = x+2) out.push(x);