OFFSET
3,2
LINKS
Amiram Eldar, Table of n, a(n) for n = 3..10002
FORMULA
MATHEMATICA
EulerPhi[Select[Range[3, 150], SquareFreeQ]]/2 (* Amiram Eldar, Mar 10 2024 *)
PROG
(PARI) H(n) = eulerphi(n)/2;
j=[]; for(n = 3, 200, if(issquarefree(n), j = concat(j, H(n)))); j
CROSSREFS
KEYWORD
nonn
AUTHOR
Jason Earls, Jul 21 2001
STATUS
approved