a(4)=5:1234,123|4,124|3,134|2,1|234。
a(5)=26:12345,1234|5,1235|4,123|45,123|4|5,1245|3,124|35,124|3|5,125|34,12|345,125| 3|4,1345|2,134|25,134|2|5,135|24,13|245,135| 2|4,145|23,14|235,15|234,1|2345,1|25|5,1|235|4,1.45|2|3,1|2|345。
a(6)=137:12345612345|612346|5。。。,123|456, 124|356, 125|346, 126|345, 134|256, 135|246, 136|245, 145|236, 146|235, 156|234, ..., 1|256|3|4, 1|2|356|4, 1|2|3|456.