# A145867 (b-file synthesized from sequence entry) 0 1 1 2 2 6 3 20 4 74 5 292 6 1214 7 5252 8 23468 9 107672 10 505048 11 2413776 12 11723188 13 57737032 14 287853518 15 1450697572 16 7381645844 17 37884748712 18 195947389208 19 1020610698832 20 5349968198328 21 28208066576176 22 149526042974008 23 796520870628752 24 4262367319460848