# A148474 (b-file synthesized from sequence entry) 0 1 1 1 2 2 3 6 4 20 5 65 6 241 7 889 8 3472 9 13622 10 55340 11 225557 12 940725 13 3937330 14 16738031 15 71404967 16 307999065 17 1332931401 18 5815439839 19 25450058722 20 112060278048 21 494798567807 22 2195172975521 23 9763509301815 24 43589884062136 25 195052842541424 26 875498008541850 27 3937713690439906 28 17755851945737789