OFFSET
0,2
COMMENTS
Binomial transform of A082311.
LINKS
FORMULA
G.f.: (1-3*x)/(1-9*x).
E.g.f.: 2*exp(9*x)/3 + 1/3.
a(n) = 2*9^n/3 + 0^n/3.
a(n) = 2*3^(2*n-1), for n>0. - Gionata Neri, Jun 18 2015
MATHEMATICA
Table[EulerPhi[9^n], {n, 0, 40}] (* Vladimir Joseph Stephan Orlovsky, Nov 10 2009 *)
PROG
(PARI) Vec((1-3*x)/(1-9*x) + O(x^30)) \\ Michel Marcus, Jun 18 2015
(Magma) [1] cat [2*3^(2*n-1): n in [1..20]]; // Vincenzo Librandi, Jun 20 2015
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
Paul Barry, Mar 10 2004
STATUS
approved