A244325 -id:A244325 - cp's OEIS frontend

A244324 Numbers n such that floor(antisigma(n) / n) = antisigma(n) mod n.

1, 2, 15, 20, 104, 207, 464, 650, 1023, 1952, 2975, 19359, 130304, 147455, 522752, 1207359, 5017599, 8382464

Offset: 1

Jaroslav Krizek, Jun 25 2014

nonn

Antisigma(n) = A024816(n) = sum of numbers less than n which do not divide n.
Also numbers n such that there is some number k > 0 with property: antisigma(n) = k*(n+1). Corresponding values of numbers k: 0, 0, 6, 8, 50, 102, 230, 323, 510, 974, 1486, 9678, …
Numbers n such that A244325(n) = A229110(n).

			Antisigma(19359) = 187366080 = 9678*19359 + 9678.

Cf. A024816, A244325, A229110.

[n: n in [1..1000000] | u eq 0 where u is (Floor((((n*(n+1)) div 2  - SumOfDivisors(n)) div n))) - (((((n*(n+1)) div 2)-SumOfDivisors(n)) mod (n)))]

isok(n) = my(as = n*(n+1)/2 - sigma(n)); (as\n == as % n); \\ Michel Marcus, Jun 26 2014

a(16)-a(18) from Michel Marcus, Jun 26 2014

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

Original entry on oeis.org

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

Jaroslav Krizek, Jun 25 2014

nonn

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.

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

Cf. A024816, A166069, A244324, A244325.

[k: k in [2..10000] | Floor((((k*(k+1))div 2  - SumOfDivisors(k)) div k)) lt Floor((((k*(k-1))div 2  - SumOfDivisors(k-1)) div (k-1)))];

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 *)

cp's OEIS Frontend

A244324 Numbers n such that floor(antisigma(n) / n) = antisigma(n) mod n.

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