OFFSET
1,2
LINKS
Amiram Eldar, Table of n, a(n) for n = 1..10000 (terms 1..160 from Harry J. Smith)
FORMULA
MATHEMATICA
Select[ Range[ 1, 2000 ], Mod[ #^2, EulerPhi[ #^2 ] ]==0& ]^2
Select[Range[2000]^2, Divisible[#, EulerPhi[#]]&] (* Harvey P. Dale, Dec 11 2010 *)
Join[{1}, Sort @ Flatten @ Table[2^i*3^j, {i, 2, Log2[m], 2}, {j, 0, Log[3, m/2^i], 2}]] (* Amiram Eldar, Oct 29 2020 *)
PROG
(PARI) j=[]; for(n=1, 2000, if(Mod(n^2, eulerphi(n^2))==0, j=concat(j, n^2))); j
(PARI) { n=0; for (m=1, 10^9, s=m^2; if (s%eulerphi(s)==0, write("b063755.txt", n++, " ", s); if (n==160, break)) ) } \\ Harry J. Smith, Aug 29 2009
CROSSREFS
KEYWORD
nonn
AUTHOR
Jason Earls, Aug 14 2001
EXTENSIONS
More terms from Dean Hickerson, Aug 15 2001
STATUS
approved