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A192819 Numbers which are both abundant (A005101) and anti-abundant (A192268). 1

%I #16 Jan 13 2022 04:22:42

%S 12,18,20,30,40,42,48,60,66,70,72,78,80,84,88,90,100,102,104,108,112,

%T 120,126,132,138,140,144,150,160,162,168,176,180,186,192,196,198,200,

%U 204,208,210,220,222,228,234,240,252,258,260,264,270,272,276,280,282,288

%N Numbers which are both abundant (A005101) and anti-abundant (A192268).

%C This is to abundant numbers as A192818 is to deficient numbers.

%H Amiram Eldar, <a href="/A192819/b192819.txt">Table of n, a(n) for n = 1..10000</a>

%F A005101 INTERSECTION A192268.

%t q[n_] := Total[Cases[Range[2, n - 1], _?(Abs[Mod[n, #] - #/2] < 1 &)]] > n && DivisorSigma[1, n] > 2*n; Select[Range[300], q] (* _Amiram Eldar_, Jan 13 2022 after _Michael De Vlieger_ at A066417 *)

%Y Cf. A005101, A066417, A192268, A192818.

%K nonn

%O 1,1

%A _Jonathan Vos Post_, Jul 11 2011

%E Missing term a(4) inserted and more terms added by _Amiram Eldar_, Jan 13 2022

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Last modified June 12 00:32 EDT 2024. Contains 373320 sequences. (Running on oeis4.)