# A248652 (b-file synthesized from sequence entry) 1 1 2 2 3 3 4 6 5 15 6 24 7 105 8 120 9 720 10 945 11 5040 12 10395 13 40320 14 135135 15 362880 16 2027025 17 3628800 18 34459425 19 39916800 20 479001600 21 654729075 22 6227020800 23 13749310575 24 87178291200 25 316234143225 26 1307674368000 27 7905853580625 28 20922789888000 29 213458046676875 30 355687428096000