# A121691 (b-file synthesized from sequence entry) 1 1 2 2 3 4 4 10 5 24 6 62 7 158 8 410 9 1064 10 2774 11 7236 12 18908 13 49428 14 129286 15 338254 16 885188 17 2316766 18 6064184 19 15874084 20 41555086 21 108785772 22 284792646 23 745574864 24 1951901064 25 5110072712 26 13378217392 27 35024400076 28 91694660704 29 240059002292