# A337907 (b-file synthesized from sequence entry) 2 2 3 6 4 48 5 220 6 1320 7 6930 8 39200 9 215208 10 1208340 11 6754440 12 38076192 13 214939296 14 1218641424 15 6925848930 16 39477746880 17 225542306704 18 1291514481972 19 7410367503396 20 42599109627360 21 245305128355560 22 1414839151645920 23 8172376003368720 24 47270088643265280 25 273766119948648000