# A002974 (b-file synthesized from sequence entry) 1 1 2 1 3 4 4 7 5 11 6 20 7 35 8 59 9 99 10 165 11 270 12 443 13 723 14 1161 15 1861 16 2961 17 4654 18 7279 19 11317 20 17476 21 26879 22 41132 23 62601 24 94878 25 143172 26 215115 27 321995 28 480216 29 713655 30 1057192