I'm trying to invert the sequence: (seq), I built a new function (mos) but still not working, any suggestion or trick.

function seq(num) {
  
  if(num < 2) {return 1; }
  if(num === 2) {return 2; } 
  
  if(num % 2 === 1) {
    const t = (num - 1) / 1;
    return seq(t - 1) + seq(t) + 1;
  }
  
  const t = num / 2;
  return seq(t) + seq(t + 1) + t;
  
};
function mos(q) { var i; for (let i = 2; i < 1000; i++) { if(seq(i-2)===q){return i;}}
    
}; document.write("mos(15): "+mos(22)+"<br>");```