A367493 - OEIS

%I #9 Nov 20 2023 23:04:58

%S 0,1,8,97,1024,20450,279936,7509953,144295424,4570291850,100000000000,

%T 4491754172274,106993205379072,5221973073321002,171975117132398592,

%U 8931527427394008833,295147905179352825856,20290116242888952838355,708235345355337676357632,51879761166564630630389778

%N a(n) = Sum_{d|n} (n-d)^n.

%F a(n) = Sum_{k=0..n} (-1)^k*binomial(n,k)*n^(n-k)*sigma_k(n).

%t a[n_]:=Sum[(n-d)^n,{d,Divisors[n]}]; Array[a,20] (* _Stefano Spezia_, Nov 20 2023 *)

%o (Python)

%o from sympy import divisors

%o def A367493(n): return sum((n-d)**n for d in divisors(n, generator=True))

%Y Cf. A094471, A367326, A367327, A367368.

%K nonn

%O 1,3

%A _Chai Wah Wu_, Nov 20 2023