OFFSET
1,2
LINKS
Vincenzo Librandi, Table of n, a(n) for n = 1..17
FORMULA
a(n) = A166470(n-1)/2. - Alois P. Heinz, Sep 16 2022
MATHEMATICA
Nest[Append[#, 2Times@@Take[#, -2]]&, {1, 3}, 10] (* Harvey P. Dale, Apr 20 2011 *)
RecurrenceTable[{a[1] == 1, a[2] == 3, a[n] == 2 a[n-2] a[n-1]}, a, {n, 12}] (* Vincenzo Librandi, Jun 19 2016 *)
nxt[{a_, b_}]:={b, 2*a*b}; NestList[nxt, {1, 3}, 10][[;; , 1]] (* Harvey P. Dale, Apr 08 2023 *)
PROG
(Magma) I:=[1, 3]; [n le 2 select I[n] else 2*Self(n-2)*Self(n-1): n in [1..11]]; // Vincenzo Librandi, Jun 19 2016
(SageMath) [2^(fibonacci(n)-1)*3^fibonacci(n-1) for n in range(1, 13)] # G. C. Greubel, Jul 30 2024
CROSSREFS
KEYWORD
nonn
AUTHOR
Giovanni Teofilatto, Mar 26 2010
EXTENSIONS
Formula replaced by a non-redundant one by R. J. Mathar, Mar 30 2010
STATUS
approved