function sumDig (n, base) {
let sum = 0;
while (n) {
sum += n % base;
n = (n - n % base) / base;
}
return sum;
}
function fun(rangMin, rangMax, base, mulMin, mulMax) {
for (let i = rangMin; i <= rangMax; i++) {
for (let j = mulMin; j <= mulMax; j++) {
if (sumDig(i, base) != sumDig(i*j, base)) break;
if (j == mulMax) console.log(i);
}
}
}
fun (1, 999999, 7, 2, 823543);