

A238231


Numbers n such that if x=phi(n)*tau(n)sigma(n)n then n=phi(x)*tau(x)sigma(x)x.


0




OFFSET

1,1


COMMENTS

a(8) > 2*10^9.  Giovanni Resta, Mar 26 2014


LINKS

Table of n, a(n) for n=1..7.


EXAMPLE

Fixed points: 376,...
phi(594) = 180, tau(594) = 16, sigma(594) = 1440 and 180*16  1440  594 = 846.
phi(846) = 276, tau(846) = 12, sigma(846) = 1872 and 276*12  1872  846 = 594.


MAPLE

with(numtheory); P:=proc(q)local a, n;
for n from 1 to q do a:=phi(n)*tau(n)sigma(n)n;
if a>0 and phi(a)*tau(a)sigma(a)a=n then print(n);
fi; od; end: P(10^6);


CROSSREFS

Cf. A000005, A000010, A000203, A238225A238230.
Sequence in context: A251652 A251645 A259769 * A008853 A188007 A251644
Adjacent sequences: A238228 A238229 A238230 * A238232 A238233 A238234


KEYWORD

nonn,more


AUTHOR

Paolo P. Lava, Feb 20 2014


STATUS

approved



