OFFSET
0,1
LINKS
Vincenzo Librandi, Table of n, a(n) for n = 0..500
FORMULA
a(n) = (3^(2*n + 3) + 2^n) / 7.
PROG
(Magma) [(3^(2*n + 3) + 2^n)/7: n in [0..20]]; // Vincenzo Librandi, Jul 17 2011
KEYWORD
nonn,easy
AUTHOR
Reinhard Zumkeller, Apr 03 2011
STATUS
approved