%I #17 Nov 21 2023 12:17:23

%S 1,2,3,4,6,8,10,12,18,24

%N Numbers n such that (n/tau(n) - sigma(n)/n) < 1.

%C Numbers n such that A245776(n)/A245777(n) = n/A000005(n) - A000203(n)/n < 1.

%C Finite sequence with 10 terms.

%e 24 is in sequence because 24/tau(24) - sigma(24)/24 = 24/8 - 60/24 = 1/2.

%t a245779[n_Integer] :=

%t Select[Range[n],

%t If[#/DivisorSigma[0, #] - DivisorSigma[1, #]/# < 1, True, False] &]; a245779[1000] (* _Michael De Vlieger_, Aug 07 2014 *)

%t Select[Range[25],#/DivisorSigma[0,#]-DivisorSigma[1,#]/#<1&] (* _Harvey P. Dale_, Nov 21 2023 *)

%o (Magma) [n:n in [1..1000000] | (Numerator((n /(#[d: d in Divisors(n)]))-(SumOfDivisors(n)/n))) / (Denominator((n/(#[d: d in Divisors(n)]))-(SumOfDivisors(n)/n))) lt 1]

%o (PARI)

%o for(n=1,10^3, if(n/numdiv(n) - sigma(n)/n < 1, print1(n,", "))) \\ _Derek Orr_, Aug 02 2014

%Y Cf. A000005, A000203, A245776, A245777, A245778, A245782.

%K nonn,fini,full

%O 1,2

%A _Jaroslav Krizek_, Aug 02 2014