# A164552 (b-file synthesized from sequence entry) 0 1 1 10 2 90 3 780 4 6660 5 56520 6 478440 7 4045680 8 34194960 9 288969120 10 2441780640 11 20632294080 12 174334109760 13 1473040494720 14 12446462643840 15 105166336884480 16 888602163298560 17 7508235853048320 18 63440765337623040 19 536042108460026880