OFFSET
1,2
LINKS
Donovan Johnson, Table of n, a(n) for n = 1..1000
MATHEMATICA
abu[x_] := Abs[DivisorSigma[1, x]-2*x]; Do[If[ !Greater[abu[n], Sqrt[n]//N]&& OddQ[n], Print[n]], {n, 1, 100000}]
PROG
(PARI) isok(k) = k % 2 && (sigma(k)-2*k)^2 <= k; \\ Amiram Eldar, Mar 02 2025
CROSSREFS
KEYWORD
nonn,changed
AUTHOR
Labos Elemer, Oct 20 2003
STATUS
approved