A348521 Numbers k such that A348271(k) > 2*k.

3600, 5040, 6480, 7056, 7920, 9072, 9360, 11088, 11520, 12240, 13680, 14400, 16128, 16560, 18000, 20880, 22320, 25200, 32400, 35280, 39600, 44100, 45360, 46800, 55440, 56700, 57600, 58320, 58800, 61200, 63504, 65520, 68400, 69300, 71280, 75600, 77616, 79380, 80640

Offset

1,1

Comments

Odd terms exist (e.g., 349476304574870948475). What is the smallest odd term?

Links

Amiram Eldar, Table of n, a(n) for n = 1..10000

Example

3600 is a term since the sum of the noninfinitary divisors of 3600 is A348271(3600) = 8073 > 2*3600 = 7200.

Mathematica

f[p_, e_] := Module[{b = IntegerDigits[e, 2], m}, m = Length[b]; Product[If[b[[j]] > 0, 1 + p^(2^(m - j)), 1], {j, 1, m}]]; isigma[1] = 1; isigma[n_] := Times @@ f @@@ FactorInteger[n]; s[n_] := DivisorSigma[1, n] - isigma[n]; Select[Range[10^5], s[#] > 2*# &]

Crossrefs

Cf. A348271, A348274.

Similar sequence: A063846.

Sequence in context: A141781 A348627 A216682 * A175752 A179746 A096472

Adjacent sequences: A348518 A348519 A348520 * A348522 A348523 A348524

Keyword

nonn

Author

Amiram Eldar, Oct 21 2021

Status

approved