# A149377 (b-file synthesized from sequence entry) 0 1 1 1 2 4 3 12 4 48 5 168 6 734 7 2901 8 12956 9 53952 10 247794 11 1076150 12 5002284 13 22265521 14 104854868 15 476333956 16 2259433082 17 10406933888 18 49727145013 19 231743193049 20 1112557697545 21 5229835292503 22 25223740295131 23 119457136172201 24 578033615443152 25 2753450989395258 26 13365420050944659 27 63989848689178980