OFFSET
3,1
FORMULA
a(n) = (n-1)*A023022(n), n >= 3.
PROG
(PARI) h(n) = eulerphi(n)/2;
a(n) = h(n^2)-h(n);
CROSSREFS
KEYWORD
nonn
AUTHOR
Jason Earls, Jul 22 2001
STATUS
approved