A244326 Numbers n such that floor(antisigma(n)/n) < floor(antisigma(n - 1)/(n - 1)).

36, 48, 60, 72, 84, 90, 96, 108, 120, 132, 144, 156, 168, 180, 192, 210, 216, 240, 252, 264, 270, 280, 288, 300, 312, 324, 330, 336, 360, 378, 384, 390, 396, 408, 420, 432, 450, 456, 468, 480, 504, 510, 528, 540, 552, 560, 570, 576, 588, 600, 612, 624, 630, 648

Offset

1,1

Comments

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

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

Links

Jaroslav Krizek, Table of n, a(n) for n = 1..8787 (all terms < 10000)

Mathematica

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 *)

Prog

(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)))]

Crossrefs

Cf. A024816, A166069, A244324, A244325.

Sequence in context: A291713 A370266 A287840 * A357605 A064597 A119850

Adjacent sequences: A244323 A244324 A244325 * A244327 A244328 A244329

Keyword

nonn

Author

Jaroslav Krizek, Jun 25 2014

Status

approved