|
| |
|
|
A075150
|
|
a(n)=L(n)*C(n), L(n)=Lucas numbers (A000032), C(n)=reflected Lucas numbers (see comment to A061084).
|
|
2
| |
|
|
4, -1, 9, -16, 49, -121, 324, -841, 2209, -5776, 15129, -39601, 103684, -271441, 710649, -1860496, 4870849, -12752041, 33385284, -87403801, 228826129, -599074576, 1568397609, -4106118241, 10749957124, -28143753121, 73681302249, -192900153616, 505019158609, -1322157322201
(list; graph; refs; listen; history; internal format)
|
|
|
|
OFFSET
| 0,1
|
|
|
COMMENTS
| a(n)=2+(-1)^n*L(2n).
|
|
|
FORMULA
| a(n)=-2a(n-1)+2a(n-2)+a(n-3), a(0)=4, a(1)=-1, a(2)=9. G.f.: (4 + 7*x - x^2)/(1 + 2*x - 2*x^2 - x^3).
a(n) = (-1)^n*A001254(n). - R. J. Mathar, Jan 11 2012
|
|
|
MATHEMATICA
| CoefficientList[Series[(4 + 7*x - x^2)/(1 + 2*x - 2*x^2 - x^3), {x, 0, 30}], x]
LinearRecurrence[{-2, 2, 1}, {4, -1, 9}, 50] (* From Harvey P. Dale, Nov 08 2011 *)
|
|
|
CROSSREFS
| Cf. A000032, A061084.
Sequence in context: A091885 A069606 A193580 * A001254 A143763 A128626
Adjacent sequences: A075147 A075148 A075149 * A075151 A075152 A075153
|
|
|
KEYWORD
| easy,sign
|
|
|
AUTHOR
| Mario Catalani (mario.catalani(AT)unito.it), Sep 05 2002
|
| |
|
|
