Star Printing - 10

Print a recursively defined star pattern. N is a power of 3, and the pattern of size N is an N x N square.

The base pattern of size 3 has a blank center cell and one star in every other cell.

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When N is greater than 3, place eight patterns of size N/3 in a 3 x 3 grid and leave only the center (N/3) x (N/3) area blank.

The first line contains an integer N. There is an integer k such that N = 3^k and 1 <= k < 8.

Print the star pattern of size N from the first line through the N-th line.