%I #31 Aug 09 2023 00:53:20
%S 1,2,2,6,2,26,2,66,83,162,2,1250,2,898,4052,6146,2,22106,2,74242,
%T 71444,22530,2,771458,390627,106498,1062884,3039234,2,12528122,2,
%U 17825794,14289860,2228226,75031252,211754594,2,9961474,179627060,1185259522,2,2237309594,2
%N a(n) = Sum_{d|n} d^(n/d-1) * (n/d)^(d-1).
%H Seiichi Manyama, <a href="/A359004/b359004.txt">Table of n, a(n) for n = 1..5000</a>
%F a(n) = [x^n] Sum_{k>0} (n/k)^(k-1) * x^k / (1 - k * x^k).
%F If p is prime, a(p) = 2.
%t a[n_] := DivisorSum[n, #^(n/#-1) * (n/#)^(#-1) &]; Array[a, 40] (* _Amiram Eldar_, Aug 09 2023 *)
%o (PARI) a(n) = sumdiv(n, d, d^(n/d-1)*(n/d)^(d-1));
%Y Cf. A359811, A359863.
%K nonn
%O 1,2
%A _Seiichi Manyama_, Jan 16 2023