damm = [ [0, 3, 1, 7, 5, 9, 8, 6, 4, 2], [7, 0, 9, 2, 1, 5, 4, 8, 6, 3], [4, 2, 0, 6, 8, 7, 1, 3, 5, 9], [1, 7, 5, 0, 9, 8, 3, 4, 2, 6], [6, 1, 2, 3, 0, 4, 5, 9, 7, 8], [3, 6, 7, 4, 2, 0, 9, 5, 8, 1], [5, 8, 6, 9, 7, 2, 0, 1, 3, 4], [8, 9, 4, 5, 3, 6, 2, 0, 1, 7], [9, 4, 3, 8, 6, 1, 7, 2, 0, 5], [2, 5, 8, 1, 4, 3, 6, 7, 9, 0] ]; function is_valid (n) { let digits = n.toString().split("") var temp = 0 for (var i = 0; i < digits.length; i++) { temp = damm[temp][digits[i]] } return temp == 0 } console.log("Valid numbers between 5700 and 5800 are:") for (var i = 5700; i <= 5800; i++) { if (is_valid(i)) { process.stdout.write(i + " ") } } console.log("")