A048753 Composite numbers k whose product of aliquot divisors divided by number of aliquot divisors is an integer.

4, 6, 15, 16, 20, 21, 27, 33, 36, 39, 42, 45, 48, 50, 51, 56, 57, 69, 70, 75, 87, 93, 100, 105, 111, 120, 123, 129, 132, 141, 154, 159, 162, 175, 177, 182, 183, 189, 196, 198, 201, 210, 213, 219, 220, 231, 237, 238, 245, 249, 256, 266, 267, 270, 273, 275, 291

Offset

1,1

Links

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

Example

For k=6, the product of aliquot divisors is 3*2*1=6; the number of aliquot divisors is 3; 6/3 = 2 (an integer), so 6 is a term.

Mathematica

padQ[n_]:=Module[{ad=Most[Divisors[n]]}, !PrimeQ[n]&&Divisible[Times@@ad, Length[ad]]]; Select[Range[2, 300], padQ] (* Harvey P. Dale, May 07 2012 *)

Crossrefs

Cf. A007956, A032741, A048752, A048754.

Sequence in context: A284123 A135093 A141667 * A055719 A349157 A117883

Adjacent sequences: A048750 A048751 A048752 * A048754 A048755 A048756

Keyword

easy,nonn

Author

Enoch Haga

Status

approved