function range(begin, end) {
    for (let i = begin; i < end; ++i)
        yield i;
}

function triples(n) {
    return [
        [x, y, z]
        for each(x in range(1, n + 1))
        for each(y in range(x, n + 1))
        for each(z in range(y, n + 1))
        if (x * x + y * y == z * z)
    ]
}

for each(var triple in triples(20))
print(triple);