Is there a more succinct way of performing the same task below? Rounding down to nearest 1 or 5mod6

Question

var n = 27;

void main() {

  while  (n>=5)

    if ( (n) % 3==0 && (n) % 2==0 ){
      print(n-1);
      break;
    }
    else if ( (n) % 3==0 &&