OFFSET
1,2
LINKS
Amiram Eldar, Table of n, a(n) for n = 1..156
PROG
(PARI) isok(n) = !(sigma(n) % n) && !(sigma(n, 3) % n); \\ Michel Marcus, Dec 26 2013
CROSSREFS
KEYWORD
nonn
AUTHOR
Labos Elemer, Oct 04 2002
EXTENSIONS
a(19)-a(25) from Amiram Eldar, May 09 2024
STATUS
approved