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A048749 Factor n, divide sum of aliquot divisors by number of aliquot divisors; append n to sequence if quotient is integral and not previously seen. 2
6, 15, 30, 33, 44, 49, 51, 69, 81, 87, 114, 117, 120, 123, 124, 141, 159, 164, 170, 177, 213, 244, 249, 252, 267, 270, 276, 282, 284, 303, 320, 321, 339, 345, 366, 393, 404, 411, 427, 447, 462, 501, 511, 513, 519, 524, 529, 534, 537, 570, 573, 590, 591, 604 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

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

EXAMPLE

a(2)=15; for n=15 the sum of aliquot divisors is 9; number of aliquot divisors is 3; 9/3=3. The quotient 3 is the mean aliquot divisor and this is the first time that 3 has occurred.

MATHEMATICA

(Select[{Mean[Most[Divisors[#]]], #}& /@ Select[Range[300], CompositeQ], IntegerQ[#[[1]]]&] // Sort // Split[#, #1[[1]] == #2[[1]]&]&)[[All, 1]][[All, 2]] // Sort (* Amiram Eldar, Sep 06 2019 after Jean-Fran├žois Alcover at A048747 *)

CROSSREFS

Cf. A001065, A023883, A032741, A048747.

Sequence in context: A229063 A025212 A024972 * A097889 A256874 A250121

Adjacent sequences:  A048746 A048747 A048748 * A048750 A048751 A048752

KEYWORD

easy,nonn

AUTHOR

Enoch Haga

STATUS

approved

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Last modified February 28 10:49 EST 2020. Contains 332323 sequences. (Running on oeis4.)