OFFSET
1,2
LINKS
Harry J. Smith, Table of n, a(n) for n = 1..200
MAPLE
with(numtheory):with(combinat):a:=n->phi(binomial(2*n, n)): seq(a(n), n=1..25); # Zerinvary Lajos, Oct 05 2007
MATHEMATICA
f[n_] := EulerPhi[Binomial[2n, n]]; Table[f[n], {n, 100}] (* Enrique Pérez Herrero, Jan 31 2012 *)
PROG
(SageMath) [euler_phi(binomial(2*n, n))for n in range(1, 26)] # Zerinvary Lajos, Jun 06 2009
(PARI) a(n) = eulerphi(binomial(2*n, n)); \\ Harry J. Smith, Apr 12 2010
CROSSREFS
KEYWORD
nonn
AUTHOR
Benoit Cloitre, Jan 26 2002
STATUS
approved