|
|
A097133
|
|
a(n) = 3*Fibonacci(n) + (-1)^n.
|
|
4
|
|
|
1, 2, 4, 5, 10, 14, 25, 38, 64, 101, 166, 266, 433, 698, 1132, 1829, 2962, 4790, 7753, 12542, 20296, 32837, 53134, 85970, 139105, 225074, 364180, 589253, 953434, 1542686, 2496121, 4038806, 6534928, 10573733, 17108662, 27682394, 44791057, 72473450, 117264508
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
OFFSET
|
0,2
|
|
COMMENTS
|
|
|
LINKS
|
|
|
FORMULA
|
G.f.: (1+2*x+2*x^2)/((1+x)*(1-x-x^2));
a(n) = 2*a(n-2)+a(n-3);
|
|
MATHEMATICA
|
CoefficientList[Series[(1+2x+2x^2)/((1+x)(1-x-x^2)), {x, 0, 40}], x] (* or *) LinearRecurrence[{0, 2, 1}, {1, 2, 4}, 40] (* Harvey P. Dale, May 07 2011 *)
|
|
PROG
|
(Haskell)
a097133 n = a097133_list !! n
a097133_list = 1 : 2 : 4 : zipWith (+)
(map (* 2) $ tail a097133_list) a097133_list
|
|
CROSSREFS
|
|
|
KEYWORD
|
easy,nonn,changed
|
|
AUTHOR
|
|
|
STATUS
|
approved
|
|
|
|