# A002978 (b-file synthesized from sequence entry) 1 0 2 0 3 4 4 0 5 12 6 8 7 48 8 96 9 320 10 888 11 2748 12 8384 13 26340 14 83568 15 268864 16 873648 17 2865216 18 9470784 19 31525524 20 105594912 21 355673804 22 1204059144 23 4094727168 24 13983145888 25 47932777680 26 164881688088 27 568990371212 28 1969356192624 29 6834965581764 30 23782468159920