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A048753 Composite n whose product of aliquot divisors divided by number of aliquot divisors is integral. 1
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 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Table of n, a(n) for n=1..57.

EXAMPLE

a(2)=6; for n=6 product of aliquot divisors is 3*2*1=6; 6/3, number of aliquot divisors = 2. Since 2 is integral, append 6 to sequence.

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

A048752 and A048754.

Sequence in context: A284123 A135093 A141667 * A055719 A117883 A106387

Adjacent sequences:  A048750 A048751 A048752 * A048754 A048755 A048756

KEYWORD

easy,nonn

AUTHOR

Enoch Haga

STATUS

approved

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Last modified August 26 00:35 EDT 2019. Contains 326324 sequences. (Running on oeis4.)