A368505 a(n) = Sum_{k=0..n} n^(n-k) * k^n.
1, 1, 6, 60, 900, 18945, 536046, 19750864, 923023368, 53456736825, 3758407535410, 315059660550756, 31005946105301388, 3535337355213234025, 461813139285801522870, 68448013078470849802560, 11415281142784979557384208, 2126537819755999634260404945
Offset: 0
Keywords
Programs
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PARI
a(n) = sum(k=0, n, n^(n-k)*k^n);
Formula
a(n) ~ sqrt(2*Pi) * n^(2*n + 1/2) / (exp(n) * (log(n))^(n+1)). - Vaclav Kotesovec, Dec 28 2023