# A111275 (b-file synthesized from sequence entry) 1 1 2 2 3 3 4 6 5 10 6 24 7 49 8 130 9 336 10 980 11 2904 12 9176 13 29432 14 97356 15 326399 16 1111770 17 3825238 18 13293456 19 46553116 20 164200028 21 582706692 22 2079517924 23 7458493728 24 26874412064 25 97241528200 26 353223728624 27 1287668381250 28 4709805627484