# A121348 (b-file synthesized from sequence entry)
2 1
3 12
4 456
5 9360
6 155520
7 21772800
8 1146700800
9 44503603200
10 11860515072000
11 1237663494144000
12 107797432393728000
13 36342886035456000000
14 6476053728774389760000
15 1089563850990959984640000