# A005909 (b-file synthesized from sequence entry) 0 0 1 2 2 3 3 7 4 15 5 35 6 80 7 185 8 428 9 991 10 2295 11 5316 12 12314 13 28525 14 66078 15 153070 16 354588 17 821407 18 1902799 19 4407857 20 10210855 21 23653572 22 54793793 23 126930502 24 294036085 25 681138245 26 1577865210 27 3655144370