# A124711 (b-file synthesized from sequence entry) 0 1 1 18 2 52 3 120 4 320 5 848 6 2314 7 6374 8 17752 9 49800 10 140582 11 398834 12 1136270 13 3248718 14 9316828 15 26790080 16 77212552 17 222993608 18 645193126 19 1869809474 20 5426815810 21 15771487250 22 45891045208 23 133679744924 24 389803622998