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%I #17 Sep 30 2019 18:10:34
%S 36,48,72,80,96,108,120,144,160,168,180,192,200,216,224,240,252,264,
%T 280,288,300,312,320,324,336,352,360,384,392,396,400,408,416,432,448,
%U 456,468,480,504,528,540,552,560,576,588,600,612,624,640,648,672,684
%N Nonunitary abundant numbers: the sum of the nonunitary divisors of n is larger than n; i.e., sigma(n) - usigma(n) > n.
%H Amiram Eldar, <a href="/A064597/b064597.txt">Table of n, a(n) for n = 1..10000</a> (terms 1..1000 from Harry J. Smith)
%e The sum of the nonunitary divisors of 36 is 2 + 3 + 6 + 12 + 18 = 41.
%t nusigma[ n_ ] := DivisorSigma[ 1, n ]-Times@@(1+Power@@#&/@FactorInteger[ n ]); For[ n=1, True, n++, If[ nusigma[ n ]>n, Print[ n ] ] ]
%o (PARI) usigma(n)= { local(f,s=1); f=factor(n); for(i=1, matsize(f)[1], s*=1 + f[i, 1]^f[i, 2]); return(s) } { n=0; for (m=1, 10^9, if (sigma(m) - usigma(m) > m, write("b064597.txt", n++, " ", m); if (n==1000, break)) ) } \\ _Harry J. Smith_, Sep 19 2009
%Y Cf. A048146, A063846, A064591, A064598.
%K nonn,easy
%O 1,1
%A _Dean Hickerson_, Sep 25 2001
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