OFFSET
1,2
LINKS
Michel Marcus, Table of n, a(n) for n = 1..100
Prime Puzzles, Puzzle 451
EXAMPLE
For n = 207308300630926047626012940 = 2^2*3^4*5*7*11*13^3*17^3*29^2*31^3*37^2*67^2
phi(n) = 2^18*3^9*5^2*7*11*13^2*17^2*29*31^2*37*67 and
sigma(n) = 2^16*3^6*5^2*7^5*11^2*13^2*17*29*31*37*67^2
have the same prime factors.
CROSSREFS
KEYWORD
nonn,fini
AUTHOR
Michel Marcus, Jul 09 2012
STATUS
approved