a(2)=24:奇数的24个组合分为2部分<7:
1: (0,1), (1,0);
3: (0,3), (3,0), (1,2), (2,1);
5: (0,5), (5,0), (1,4), (4,1), (2,3), (3,2);
7: (1,6), (6,1), (2,5), (5,2), (3,4), (4,3);
9: (3,6), (6,3), (4,5), (5,4);
11: (5,6),(6,5). (结束)
a(4)=1200=8*a(3)-7*a(2)=8*171-7*24。
a(4)=1200=M^n*[1,0]中的右项=[A034494号(4) ,a(4)]=[1201,1200]。