# A375671 (b-file synthesized from sequence entry)
0 1
1 0
2 4
3 6
4 88
5 420
6 5148
7 44520
8 587424
9 7203168
10 109106640
11 1689621120
12 29620245312
13 546547098240
14 10989238893696
15 233884517368320
16 5324618721070080
17 128058198711690240
18 3260308438558826496
19 87336328336058603520
20 2459915920512955929600