# A156291 (b-file synthesized from sequence entry) 1 1 2 3 3 8 4 21 5 104 6 315 7 105 8 1040 9 5355 10 19344 11 3255 12 125840 13 1826055 14 15107664 15 86590175 16 9765 17 880880 18 23738715 19 317260944 20 2684295425 21 16476602400 22 1240155 23 962801840 24 129637122615 25 6196423497264 26 150285647959475 27 2261529015616800 28 23895819265962735