# A148468 (b-file synthesized from sequence entry) 0 1 1 1 2 2 3 6 4 19 5 63 6 228 7 853 8 3303 9 13129 10 53284 11 219809 12 920251 13 3898392 14 16683106 15 72047117 16 313513987 17 1373636939 18 6054897529 19 26832276225 20 119480099586 21 534329193514 22 2398901718584 23 10808275537214 24 48854155081710 25 221476765120080 26 1006775733279628 27 4587970914295101 28 20956052719317802