OFFSET
0,2
FORMULA
a(n) = (3^(n-2) + 1) * a(n-1). - Vincenzo Librandi, Nov 10 2012
PROG
(Magma) I:=[1, 3, 10]; [n le 3 select I[n] else (3^(n-2)+1)*Self(n-1): n in [1..15]]; // Vincenzo Librandi, Nov 10 2012
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
STATUS
approved