# A027289 (b-file synthesized from sequence entry) 2 1 3 3 4 18 5 55 6 264 7 847 8 3744 9 12465 10 52868 11 180895 12 749220 13 2617173 14 10680656 15 37915317 16 153240864 17 551019963 18 2212417314 19 8038946075 20 32129224712 21 117758845827 22 469105048654 23 1731917060158 24 6882935960496 25 25569740611270 26 101442831429264 27 378875492015643