# A090115 (b-file synthesized from sequence entry) 1 1 2 1 3 4 4 15 5 252 6 924 7 11440 8 43758 9 497420 10 13123110 11 54627300 12 1251677700 13 12033222880 14 52860229080 15 511738760544 16 10363194502115 17 197548686920970 18 925029565741050 19 17302625882942400 20 161884603662657876