Case 1: length = 1 for N = 1

Case 2: length = 2 for N = 2

Case 3: length = 8 for N = 3

Case 4: length = 3 for N = 4

Case 5: length = 6 for N = 5

Case 6: length = 9 for N = 6

Case 7: length = 17 for N = 7

Case 8: length = 4 for N = 8

Case 9: length = 20 for N = 9

Case 10: length = 7 for N = 10

Case 11: length = 119 for N = 97

Case 12: length = 153 for N = 775