[0,1,2,2,3,4,3,4,5,6,4,5,6,7,8,5,6,7,8,9,10,6,7,8, 9,10,11,12,7,8,9,10,11,12,13,14,8,9,10,11,12,13, 14,15,16,9,10,11,12,13,14,15,16,17,18,10,11,12,13, 14,15,16,17,18,19,20]