A348583 -id:A348583 - cp's OEIS frontend

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A348584 Numbers k such that k | A328258(k).

Original entry on oeis.org

1, 12, 56, 180, 992, 16256, 127400, 441000, 2646000, 67100672, 325458000, 2758909440, 17179738112, 274877382656

Offset: 1

Amiram Eldar, Oct 24 2021

The corresponding ratios A113184(k)/k are 1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -2, -1, -1, ...
If p is a Mersenne exponent (A000043), then 2^p*(2^p-1) (twice an even perfect number) is a term with ratio A328258(k)/k = -1.
If there exists an odd term k, then it is a unitary multiply-perfect number (A327158), since A328258(k) = A034448(k) for an odd k.

			12 is a term since A328258(12) = -12 is divisible by 12.

The unitary version of A348583.
A139256 is a subsequence.
Cf. A000043, A034448, A327158, A328258.

f[p_, e_] := 1 - (-1)^p*(p^e); s[1] = 1; s[n_] := Times @@ f @@@ FactorInteger[n]; Select[Range[3*10^6], Divisible[s[#], #] &]

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