# A337507 (b-file synthesized from sequence entry)
0 0
1 0
2 1
3 4
4 24
5 176
6 1540
7 15672
8 181916
9 2372512
10 34348932
11 546674120
12 9486840748
13 178285201008
14 3607174453844
15 78177409231768
16 1806934004612220
17 44367502983673664
18 1153334584544496676
19 31643148872573831016