# A002570 (b-file synthesized from sequence entry) 1 1 2 1 3 6 4 11 5 36 6 85 7 235 8 600 9 1590 10 4140 11 10866 12 28416 13 74431 14 194821 15 510096 16 1335395 17 3496170 18 9153025 19 23963005 20 62735880 21 164244756 22 429998256 23 1125750156 24 2947252056 25 7716006181 26 20200766305 27 52886292930 28 138458112275 29 362488044120