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A023886 Average of proper divisors (excluding 1) is an integer. 6
4, 8, 9, 15, 18, 21, 25, 27, 33, 35, 39, 45, 49, 51, 55, 57, 63, 65, 69, 75, 77, 81, 85, 87, 91, 93, 95, 98, 99, 111, 115, 117, 119, 121, 123, 125, 128, 129, 133, 141, 143, 145, 147, 153, 155, 159, 161, 162, 169, 171, 175, 177, 183, 185, 187, 201, 203 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Vincenzo Librandi, Table of n, a(n) for n = 1..1000

MATHEMATICA

Select[Range[210], IntegerQ[Mean[Rest[Most[Divisors[#]]]]]&] (* Harvey P. Dale, Feb 20 2011 *)

CROSSREFS

Sequence in context: A326692 A336663 A329936 * A158337 A161542 A131195

Adjacent sequences: A023883 A023884 A023885 * A023887 A023888 A023889

KEYWORD

nonn

AUTHOR

Olivier Gérard

EXTENSIONS

Clarified definition -- Harvey P. Dale, Feb 20 2011

STATUS

approved

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Last modified January 29 15:13 EST 2023. Contains 359923 sequences. (Running on oeis4.)