# A335991 (b-file synthesized from sequence entry)
0 1
1 1
2 4
3 8
4 36
5 3456
6 172800
7 10368000
8 3810240000
9 177811200000
10 9957427200000
11 75278149632000000
12 1912817782149120000000
13 53023308921173606400000000
14 17742659631203112173568000000000
15 426249654980023566857797632000000000