# A006365 (b-file synthesized from sequence entry) 0 1 1 1 2 3 3 8 4 24 5 72 6 229 7 740 8 2460 9 8317 10 28590 11 99556 12 350661 13 1246998 14 4471801 15 16153007 16 58722226 17 214687361 18 788855637 19 2911701588 20 10790952975 21 40139185202 22 149805575022 23 560804604385 24 2105273566444 25 7923577070408 26 29892583708055 27 113020768615090 28 428190609376563 29 1625319129822979 30 6180270575440241