# A004246 (b-file synthesized from sequence entry)
4 8
5 25
6 144
7 735
8 4608
9 39285
10 362000
11 3628185
12 40808448
13 478988081
14 6227101888
15 87248724750
16 1300561920000
17 20922788404479
18 355587467242752
19 6402373698206889
20 121810906419200000