# A073985 (b-file synthesized from sequence entry) 1 0 2 0 3 3 4 24 5 180 6 1296 7 9072 8 54432 9 297432 10 1658880 11 9722592 12 58576608 13 356638464 14 2173796352 15 13162730688 16 79012495872 17 472093588224 18 2821109907456 19 16894457846784 20 101366747080704 21 608764662139392 22 3656096522698752 23 21947538146863104 24 131685972252346368