OFFSET
1,2
LINKS
Donovan Johnson, Table of n, a(n) for n = 1..1000
PROG
(PARI) isok(n) = {for (x=1, n, if (eulerphi(x)*sigma(x) == n, return (1)); ); return (0); } \\ Michel Marcus, Dec 04 2013
CROSSREFS
KEYWORD
nonn
AUTHOR
Benoit Cloitre, Apr 27 2003
STATUS
approved