# A002462 (b-file synthesized from sequence entry) 0 1 1 1 2 9 3 50 4 1225 5 7938 6 106722 7 736164 8 41409225 9 295488050 10 4266847442 11 31102144164 12 914057459042 13 6760780022500 14 100583849722500 15 751920156592200 16 90324408810638025 17 680714748752836050 18 10294760089163261250 19 78080479568224402500 20 2375208188465386324050