OFFSET
1,2
LINKS
Alois P. Heinz, Table of n, a(n) for n = 1..20000
MAPLE
A061884 := proc(n) local b, d: b := 0; for d from 1 to n do if irem(n, d)=0 then b := b+phi(lcm(d, n/d)); fi; od; RETURN(b); end:
MATHEMATICA
Table[Plus @@ Map[ EulerPhi[LCM[ #, n/# ]] &, Select[ Range@n, (Mod[n, # ] == 0) &]], {n, 65}] (* Robert G. Wilson v, Sep 30 2006 *)
PROG
(PARI) a(n)=sumdiv(n, d, eulerphi(lcm(d, n/d))) \\ Charles R Greathouse IV, Feb 21 2013
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
Vladeta Jovovic, May 12 2001
STATUS
approved