# A026965 (b-file synthesized from sequence entry) 0 1 1 3 2 10 3 25 4 66 5 154 6 360 7 810 8 1810 9 3982 10 8700 11 18850 12 40614 13 87030 14 185680 15 394570 16 835578 17 1763998 18 3713700 19 7798770 20 16340302 21 34166086 22 71303160 23 148548250 24 308980386 25 641728494 26 1330992460 27 2757055810 28 5704253430