stacked on setinterval

I try to make a loop with a dynamic intervaltime.
I don't know how to fix this.
Do someone have a suggestion for me?

var c = 1;
var time = 15;
function flash(time){
  on = !on;
  digitalWrite(A0, on);
  
  c++;
  if(c >= 20){
    digitalWrite(LED1, 1);
  } 
  if(c >= 40){
    digitalWrite(LED2, 1);
  }
  if(c >= 60){
    digitalWrite(LED3, 1);
  }
  if(c >= 80){
    c = 0;
    digitalWrite([LED1, LED2, LED3],0);
    time += 25;
    return time;
    
  }
}

setInterval(flash,time);

Thanks!