A353901 Numbers k such that A353900(k) is divisible by k.

1, 6, 28, 56, 1104, 2208, 2178540, 4357080, 6499584, 12999168

Offset: 1

Author

Amiram Eldar, May 10 2022

Keywords

• nonn
• more

Comments

a(11) > 8*10^10, if it exists.

The corresponding ratios A353900(k)/k are 1, 2, 2, 1, 2, 1, 4, 2, 2, 1, ...

Examples

			6 is a term since A353900(6) = 12 is divisible by 6.
56 is a term since A353900(56) = 56 is divisible by 56.
		

Crossrefs

Cf. A353900.

Similar sequences: A007691, A189000, A327158, A348601.

Programs

Mathematica

f[p_, e_] := 1 + Sum[p^(2^k), {k, 0, Floor[Log2[e]]}]; s[1] = 1; s[n_] := Times @@ f @@@ FactorInteger[n]; Select[Range[6.5*10^6], Divisible[s[#], #] &]