# A155613 (b-file synthesized from sequence entry) 0 1 1 6 2 56 3 486 4 4016 5 32526 6 261416 7 2094966 8 16770656 9 134198046 10 1073682776 11 8589757446 12 68718945296 13 549754219566 14 4398041728136 15 35184357739926 16 281474933663936 17 2251799684545086 18 18014398122061496 19 144115186913594406