# A150071 (b-file synthesized from sequence entry) 0 1 1 2 2 6 3 18 4 64 5 220 6 792 7 2844 8 10508 9 38726 10 144976 11 542780 12 2051752 13 7761764 14 29554000 15 112658878 16 431389136 17 1653790724 18 6360803312 19 24493717106 20 94551791464 21 365396555846 22 1414800367992 23 5483604012036 24 21286461979104 25 82707275267172 26 321758489858736 27 1252797572552836 28 4883010365872848