# A004367 (b-file synthesized from sequence entry)
12 1
13 78
14 3486
15 117480
16 3321960
17 83291670
18 1913554188
19 41146859952
20 840261910995
21 16466440817750
22 312058705015200
23 5752562036128128
24 103619293824707388
25 1830311583210984300
26 31794836537065001400