|
Search: id:A128534
|
|
|
| A128534 |
|
F(n)*L(n-1) where F=Fibonacci and L=Lucas numbers. |
|
+0
3
|
|
| 0, 2, 1, 6, 12, 35, 88, 234, 609, 1598, 4180, 10947, 28656, 75026, 196417, 514230, 1346268, 3524579, 9227464, 24157818, 63245985
(list; graph; listen)
|
|
|
OFFSET
|
0,2
|
|
|
COMMENT
|
Generally, F(n)*L(n+k) = F(2*n + k) + F(k)*(-1)^(n+1). If k=0 the sequence is A001906; if k=1 it is A081714.
|
|
FORMULA
|
a(n) = F(2*n - 1) + (-1)^(n+1), assuming F(0)=0 and L(0)=2.
a(n)=2*a(n-1)+2*a(n-2)-a(n-3). G.f.: -x*(-2+3*x)/((1+x)*(x^2-3*x+1)). [From R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Apr 16 2009]
|
|
EXAMPLE
|
a(5) = 35 because F(5)*L(4) = 5*7
|
|
CROSSREFS
|
Cf. A001906, A081714, A128533, A128535.
Sequence in context: A113025 A113216 A081064 this_sequence A002562 A136456 A123968
Adjacent sequences: A128531 A128532 A128533 this_sequence A128535 A128536 A128537
|
|
KEYWORD
|
easy,nonn
|
|
AUTHOR
|
Axel Harvey (ax(AT)hirsig.ca), Mar 08 2007
|
|
|
Search completed in 0.002 seconds
|
