# A006297 (b-file synthesized from sequence entry) 2 1 3 10 4 167 5 1720 6 24164 7 256116 8 3392843 9 36703824 10 472592916 11 5188948072 12 65723863196 13 729734918432 14 9145847808784 15 102432266545800 16 1274461449989715 17 14373136466094880 18 177882700353757460 19 2017523504473479992 20 24868664942648145372