# A067636 (b-file synthesized from sequence entry)
0 2
1 20
2 210
3 2352
4 27720
5 339768
6 4294290
7 55621280
8 734959368
9 9873696560
10 134510127752
11 1854385377600
12 25828939188000
13 362995937665200
14 5141806953167250
15 73343003232628800
16 1052697272275341000
17 15194039267330154000
18 220410039466873456200