Problem 2147. Langston's Ant

The Langston's Ant Challenge is to determine the number of Black squares after K Ant moves.

An infinite white board has an Ant at the center. Direction is not required.

Movement and Affect:

1) At a white square, turn 90° right, White goes to Black, move forward one unit
2) At a black square, turn 90° left, Black goes to White, move forward one unit

After a given number of moves how many Black squares are present.

Input: K, number of moves from 100 to 12000

Output: BLK, number of Black squares

Example: K=5, BLK=3 [00000;00010;00110]

Note: After 11000 moves a pattern emerges