# A147727 (b-file synthesized from sequence entry) 1 1 2 2 3 6 4 16 5 54 6 232 7 936 8 3880 9 17302 10 81584 11 409012 12 2169742 13 11998726 14 69653068 15 426511054 16 2718410098 17 18114464012