int[] sizes = {10, 20, 30, 40, 50};

void setup() {
  size(400, 200);
  noStroke();
}

void draw() {
  background(255);
  fill(150); //sample color
  for (int i = 0; i < sizes.length; i++) {
    ellipse(60 * (i + 1), height / 2, sizes[i], sizes[i]);
  }
}