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Nonexponential multiply-perfect numbers: numbers k such that k | A160135(k).
4

%I #6 Oct 25 2021 11:11:28

%S 1,6,40,234,588,89376,10805558400

%N Nonexponential multiply-perfect numbers: numbers k such that k | A160135(k).

%C The corresponding quotients A160135(k)/k are 1, 1, 1, 1, 1, 2, 3, ...

%C a(8) > 1.5*10^10, if it exists.

%e 6 is a term since its nonexponential divisors are 1, 2 and 3, so A160135(6) = 1 + 2 + 3 = 6 which is divisible by 6.

%e 40 is a term since its nonexponential divisors are 1, 2, 4, 5, 8 and 20, so A160135(40) = 1 + 2 + 4 + 5 + 8 + 20 = 40 which is divisible by 40.

%t esigma[n_] := Times @@ (Sum[First[#]^d, {d, Divisors[Last[#]]}] &) /@ FactorInteger[n]; Select[Range[1000], Divisible[DivisorSigma[1, #] - esigma[#], #] &]

%Y Cf. A160135.

%Y Similar sequences: A007691, A064594, A064595, A189000, A327158.

%K nonn,more

%O 1,2

%A _Amiram Eldar_, Oct 25 2021