OFFSET
1,1
LINKS
Donovan Johnson, Table of n, a(n) for n = 1..500
PROG
(PARI) for(n=1, 10^8, s=sigma(n); if(sigma(s)%s==eulerphi(n), print(n))) \\ Donovan Johnson, Feb 25 2013
CROSSREFS
KEYWORD
nonn
AUTHOR
Benoit Cloitre, Feb 19 2002
STATUS
approved