# A216541 (b-file synthesized from sequence entry) 0 1 1 3 2 8 3 35 4 154 5 756 6 3828 7 20163 8 108680 9 598026 10 3342404 11 18929092 12 108374252 13 626264700 14 3647936160 15 21396522915 16 126262239570 17 749087596620 18 4465444206300 19 26733390275130 20 160663411399920 21 968937572793060 22 5862111195487560 23 35569106862459300 24 216395609659221564