OFFSET
1,2
LINKS
Harry J. Smith, Table of n, a(n) for n=1,...,1000
EXAMPLE
5 is in the sequence because phi(5) = 4, sigma(5) = 6, phi(4) = 2 = phi(6).
PROG
(PARI) { n=0; for (m=1, 10^9, if (eulerphi(eulerphi(m)) == eulerphi(sigma(m)), write("b065555.txt", n++, " ", m); if (n==1000, return)) ) } \\ Harry J. Smith, Oct 22 2009
CROSSREFS
KEYWORD
nonn
AUTHOR
Walter Nissen, Nov 28 2001
STATUS
approved