%I #10 May 12 2019 06:51:04
%S 33075,99225,165375,231525,259875,297675,363825,429975,467775,496125,
%T 552825,562275,571725,606375,628425,675675,694575,716625,760725,
%U 779625,798525,826875,848925,883575,893025,921375,937125,959175,1003275
%N Odd nonunitary abundant numbers.
%H Amiram Eldar, <a href="/A094889/b094889.txt">Table of n, a(n) for n = 1..10000</a>
%H J. A. Sellers, <a href="http://www.math.psu.edu/sellersj/mcedonan.pdf">A Note On Infinitely Many Odd Nonunitary Abundant Numbers</a>
%t f[p_, e_] := (p^(e + 1) - 1)/(p - 1); nuabQ[n_] := Times @@ (f @@@ FactorInteger[n]) - Times @@ (1 + Power @@@ FactorInteger[n]) > n; Select[Range[3, 10^6, 2], nuabQ] (* _Amiram Eldar_, May 12 2019 *)
%o (PARI) { usigma(n)=local(s=1,fac,i); fac=factor(n); for(i=1,matsize(fac)[1], s=s*(1+fac[i,1]^fac[i,2])); return(s); } nusigma(n)=sigma(n)-usigma(n); forstep(n=1,2^24,2,if(nusigma(n)>n,print1(n",")))
%Y Cf. A064597.
%K nonn
%O 1,1
%A _Lekraj Beedassy_, Jun 16 2004
%E Corrected and extended by _Jason Earls_, Jun 18 2004
|