The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation. Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A244326 Numbers n such that floor(antisigma(n)/n) < floor(antisigma(n - 1)/(n - 1)). 2

%I

%S 36,48,60,72,84,90,96,108,120,132,144,156,168,180,192,210,216,240,252,

%T 264,270,280,288,300,312,324,330,336,360,378,384,390,396,408,420,432,

%U 450,456,468,480,504,510,528,540,552,560,570,576,588,600,612,624,630,648

%N Numbers n such that floor(antisigma(n)/n) < floor(antisigma(n - 1)/(n - 1)).

%C Antisigma(n) = A024816(n) = the sum of the non-divisors of n that are between 1 and n.

%C Numbers from A166069 (multiply perfect numbers k such that sigma(k)/k > 2) are members of this sequence.

%H Jaroslav Krizek, <a href="/A244326/b244326.txt">Table of n, a(n) for n = 1..8787 (all terms < 10000)</a>

%t With[{as=Table[Floor[Total[Complement[Range[2,n],Divisors[n]]/n]],{n,1000}]},Flatten[Position[Partition[as,2,1],_?(First[#]>Last[#]&),{1},Heads->False]]]+1 (* _Harvey P. Dale_, Sep 10 2014 *)

%o (MAGMA) [n: n in [2..10000] | Floor((((n*(n+1))div 2 - SumOfDivisors(n)) div n)) lt Floor((((n*(n-1))div 2 - SumOfDivisors(n-1)) div (n-1)))]

%Y Cf. A024816, A166069, A244324, A244325.

%K nonn

%O 1,1

%A _Jaroslav Krizek_, Jun 25 2014

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified July 13 17:54 EDT 2020. Contains 335689 sequences. (Running on oeis4.)