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This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

A064598 Nonunitary deficient numbers: the sum of the nonunitary divisors of n is less than n; i.e., sigma(n) - usigma(n) < n.

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%I A064598 #17 Sep 30 2019 18:08:40
%S A064598 1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,25,26,27,
%T A064598 28,29,30,31,32,33,34,35,37,38,39,40,41,42,43,44,45,46,47,49,50,51,52,
%U A064598 53,54,55,56,57,58,59,60,61,62,63,64,65,66,67,68,69,70,71,73,74,75,76
%N A064598 Nonunitary deficient numbers: the sum of the nonunitary divisors of n is less than n; i.e., sigma(n) - usigma(n) < n.
%H A064598 Amiram Eldar, <a href="/A064598/b064598.txt">Table of n, a(n) for n = 1..10000</a> (terms 1..1000 from Harry J. Smith)
%t A064598 nusigma[ n_ ] := DivisorSigma[ 1, n ]-Times@@(1+Power@@#&/@FactorInteger[ n ]); For[ n=1, True, n++, If[ nusigma[ n ]<n, Print[ n ] ] ]
%o A064598 (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("b064598.txt", n++, " ", m); if (n==1000, break)) ) } \\ _Harry J. Smith_, Sep 19 2009
%Y A064598 Cf. A048146, A064591, A064597.
%K A064598 nonn,easy
%O A064598 1,2
%A A064598 _Dean Hickerson_, Sep 25 2001