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A023885 Not a prime and average of divisors except itself is an integer. 2
6, 9, 15, 25, 30, 33, 44, 49, 51, 69, 81, 87, 91, 114, 117, 120, 121, 123, 124, 133, 135, 141, 159, 164, 169, 170, 177, 182, 207, 213, 217, 244, 247, 249, 252, 259, 267, 270, 273, 276, 282, 284, 289, 301, 303, 306, 310, 320, 321, 339, 343, 345 (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[400], !PrimeQ[#]&&IntegerQ[Mean[Most[ Divisors[ #]]]]&] (* Harvey P. Dale, Jun 28 2011 *)

CROSSREFS

Sequence in context: A316048 A316049 A102971 * A031209 A271826 A242183

Adjacent sequences:  A023882 A023883 A023884 * A023886 A023887 A023888

KEYWORD

nonn

AUTHOR

Olivier Gérard

STATUS

approved

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Last modified April 18 22:08 EDT 2019. Contains 322237 sequences. (Running on oeis4.)