BigInteger.LucasSequence C# (CSharp) Method

        public static BigInteger[] LucasSequence(BigInteger P, BigInteger Q,
                                                 BigInteger k, BigInteger n)
        {
                if(k.dataLength == 1 && k.data[0] == 0)
                {
                        BigInteger[] result = new BigInteger[3];

                        result[0] = 0; result[1] = 2 % n; result[2] = 1 % n;
                        return result;
                }

                // calculate constant = b^(2k) / m
                // for Barrett Reduction
                BigInteger constant = new BigInteger();

                int nLen = n.dataLength << 1;
                constant.data[nLen] = 0x00000001;
                constant.dataLength = nLen + 1;

                constant = constant / n;

                // calculate values of s and t
                int s = 0;

                for(int index = 0; index < k.dataLength; index++)
                {
                        uint mask = 0x01;

                        for(int i = 0; i < 32; i++)
                        {
                                if((k.data[index] & mask) != 0)
                                {
                                        index = k.dataLength;      // to break the outer loop
                                        break;
                                }
                                mask <<= 1;
                                s++;
                        }
                }

                BigInteger t = k >> s;

                //Console.WriteLine("s = " + s + " t = " + t);
                return LucasSequenceHelper(P, Q, t, n, constant, s);
        }