OFFSET
1,3
COMMENTS
T(n,k) = gcd(n,k) phi(k). Can be seen as a generalization of n -> phi(n^2) [A002618].
LINKS
Peter Luschny, Sequences related to Euler's totient function.
EXAMPLE
1
1,2
1,1,6
1,2,2,8
1,1,2,2,20
1,2,6,4,4,12
1,1,2,2,4,2,42
MAPLE
A181538 := (n, k) -> igcd(n, k)*phi(k);
MATHEMATICA
t[n_, k_] := Block[{j = Divisors@ k}, Plus @@ (#*MoebiusMu[k/#] & /@ j)] GCD[n, k]; Table[ t[n, k], {n, 12}, {k, n}] // Flatten (* Robert G. Wilson v, Jan 19 2011 *)
CROSSREFS
KEYWORD
nonn,tabl
AUTHOR
Peter Luschny, Oct 29 2010
STATUS
approved