integer division

div.mjs

let p = 7;
for (let a = 0; a < p; a++) {
for (let b = 0; b < p; b++) {
  let arr = [];
  for (let q = 0; q < p; q++) {
  for (let r = 0; r < p; r++) {
    //if (a == (b * q + r) && r < b) arr.push([a, b, q, r]);
    if (a == (b * q + r) % p && r < b) arr.push([a, b, q, r]);
  }
  }
  if (arr.length != 1) console.log(arr);
}
}