Search: id:A023196
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%I A023196
%S A023196 6,12,18,20,24,28,30,36,40,42,48,54,56,60,66,70,72,78,80,84,88,90,96,100,
%T A023196 102,104,108,112,114,120,126,132,138,140,144,150,156,160,162,168,174,176,
%U A023196 180,186,192,196,198,200,204,208,210,216,220,222,224,228,234,240,246,252
%N A023196 Numbers n such that sigma(n) >= 2n (union of perfect (A000396) and abundant 
               (A005101) numbers).
%C A023196 These are the non-deficient numbers.
%C A023196 Comment from Max Alekseyev (maxale(AT)gmail.com), Jan 26 2005: The sequence 
               of n that give local minima for A004125, i.e. such that A004125(n-1)>
               A004125(n) and A004125(n)<A004125(n+1) coincides with this sequence 
               for the first 1014 terms. Then there appears 4095 which is a term 
               of A023196 but is not a local minima.
%C A023196 Also union of pseudoperfect and weird numbers. Cf. A005835, A006037. 
               - Frank Adams-Watters (FrankTAW(AT)Netscape.net), Mar 29 2006
%H A023196 T. D. Noe, <a href="b023196.txt">Table of n, a(n) for n=1..1000</a>
%F A023196 If n is a member so is every positive multiple of n. The "primitive" 
               members form A006039.
%t A023196 Flatten[Table[If[DivisorSigma[1, n] >= 2*n, n, {}], {n, 1, 300}]] - Roger 
               L. Bagula (rlbagulatftn(AT)yahoo.com), Sep 18 2008
%Y A023196 Cf. A004125, A006039, A000396, A005101.
%Y A023196 Sequence in context: A051774 A119357 A097216 this_sequence A005835 A007620 
               A100715
%Y A023196 Adjacent sequences: A023193 A023194 A023195 this_sequence A023197 A023198 
               A023199
%K A023196 nonn,nice
%O A023196 1,1
%A A023196 David W. Wilson (davidwwilson(AT)comcast.net)

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