# A004352 (b-file synthesized from sequence entry)
10 1
11 55
12 1770
13 43680
14 916895
15 17259390
16 300500200
17 4935847320
18 77515521435
19 1174992339235
20 17310309456440
21 249145778809200
22 3517322746798575
23 48857840214014580
24 669413654240461560
25 9064807833193439800