# A346661 (b-file synthesized from sequence entry) 0 1 1 1 2 2 3 5 4 15 5 50 6 180 7 690 8 2792 9 11857 10 52633 11 243455 12 1170525 13 5837934 14 30151474 15 161021581 16 888001485 17 5051014786 18 29600662480 19 178541105770 20 1107321666920 21 7055339825171 22 46142654894331 23 309513540865544 24 2127744119042216 25 14979904453920111 26 107932371558460341 27 795363217306369817 28 5990768203554158167 29 46094392105916344968 30 362092868720288824992