A107864 Duplicate of A099121.
1, 3, 21, 220, 3060, 53130, 1107568, 26978328, 752538150, 23667689815, 828931106355, 32006008361808, 1350990969850340, 61902409203193230, 3060335715568296000, 162392216278033616560, 9206887338937200407418
Offset: 0