%I #17 Sep 30 2019 18:08:40

%S 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 28,29,30,31,32,33,34,35,37,38,39,40,41,42,43,44,45,46,47,49,50,51,52,

%U 53,54,55,56,57,58,59,60,61,62,63,64,65,66,67,68,69,70,71,73,74,75,76

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

%H 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 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("b064598.txt", n++, " ", m); if (n==1000, break)) ) } \\ _Harry J. Smith_, Sep 19 2009

%Y Cf. A048146, A064591, A064597.

%K nonn,easy

%O 1,2

%A _Dean Hickerson_, Sep 25 2001