# A307128 (b-file synthesized from sequence entry) 0 1 1 1 2 2 3 6 4 15 5 40 6 103 7 266 8 683 9 1753 10 4481 11 11417 12 28993 13 73414 14 185424 15 467302 16 1175322 17 2950467 18 7393090 19 18492029 20 46173538 21 115102596 22 286482967 23 711990108 24 1767048214 25 4379814978 26 10842382074 27 26808912074 28 66212421302 29 163351562975 30 402575169429 31 991119918949