Collatz's Conjecture

final BigInteger TWO = new BigInteger("2");
final BigInteger THREE = new BigInteger("3");
BigInteger c = new BigInteger("12345678901234567890");
System.out.println(c);
for(; c.compareTo(BigInteger.ONE) == 1; System.out.println(c)) {
    if(c.testBit(0)) { // if odd
        c = c.multiply(THREE).add(BigInteger.ONE); // c = 3 * c + 1
    } else { // even
        c = c.divide(TWO); // c = 2 * c
    }
}