A085390 a(n) = (n(n+1)^(n-2)+0^(n-2))/(n+1).
1, 3, 20, 180, 2058, 28672, 472392, 9000000, 194871710, 4729798656, 127253992476, 3760310514688, 121096582031250, 4222124650659840, 158473248526494992, 6371827248895377408, 273260286537746369382, 12451840000000000000000
Offset: 2
Links
- Milan Janjic, Enumerative Formulas for Some Functions on Finite Sets
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