# A068878 (b-file synthesized from sequence entry) 1 2 2 24 3 60 4 720 5 40320 6 181440 7 3628800 8 479001600 9 3113510400 10 87178291200 11 20922789888000 12 177843714048000 13 6402373705728000 14 2432902008176640000 15 25545471085854720000 16 1124000727777607680000 17 620448401733239439360000