Generate one random number

[GoToLoop]

"use strict";

const FRAMES = 200, MAX_DIAM = 50, BG = 0o350;
let diam = MAX_DIAM >> 1;

function draw() {
  frameCount % FRAMES || (diam = random(MAX_DIAM));
  background(BG).circle(width >> 1, height >> 1, diam);
}