# A074403 (b-file synthesized from sequence entry) 1 0 2 0 3 2 4 6 5 16 6 45 7 128 8 448 9 1706 10 6528 11 24576 12 90110 13 327680 14 1198665 15 4438966 16 16646144 17 62914560 18 238605640 19 905969664 20 3442684722 21 13102206738 22 49977848925 23 191126044672 24 732649837760 25 2814062572336 26 10825959997440 27 41705086880768 28 160862477970870