a(5)=2*43=86,因为:
11 -> 2, 111 -> 12, 12 -> 3, 1111 -> 112, 112 -> 13, 112 -> 22,
13 -> 22, 13 -> 4, 11111 -> 1112, 1112 -> 122, 1112 -> 113, 122 -> 23,
122 -> 113, 113 -> 23, 113 -> 14, 23 -> 14, 14 -> 5,
0 -> 1,
1 -> 11, 1 -> 2, 11 -> 111, 11 -> 12, 2 -> 12, 2 -> 3, 111 -> 1111,
111 -> 112, 12 -> 112, 12 -> 13, 12 -> 22, 3 -> 13, 3 -> 4,
1111 -> 11111, 1111 -> 1112, 112 -> 1112, 112 -> 113, 112 -> 122,
13 -> 113, 13 -> 14, 13 -> 23, 22 -> 23, 22 -> 122, 4 -> 14, 4 -> 5,
其中有43个跃迁,(计算向上和向下跃迁)我们有2*43=86=A096586号(5).