A118658 a(n) = 2*F(n-1) = L(n) - F(n), where F(n) and L(n) are Fibonacci and Lucas numbers respectively.
2, 0, 2, 2, 4, 6, 10, 16, 26, 42, 68, 110, 178, 288, 466, 754, 1220, 1974, 3194, 5168, 8362, 13530, 21892, 35422, 57314, 92736, 150050, 242786, 392836, 635622, 1028458, 1664080, 2692538, 4356618, 7049156, 11405774, 18454930, 29860704, 48315634, 78176338
Offset: 0
Links
- Vincenzo Librandi, Table of n, a(n) for n = 0..1000
- Tanya Khovanova, Recursive Sequences
- Eric Weisstein's World of Mathematics, Independent Edge Set
- Eric Weisstein's World of Mathematics, Ladder Graph
- Eric Weisstein's World of Mathematics, Matching
- Eric Weisstein's World of Mathematics, Maximal Independent Vertex Set
- Eric Weisstein's World of Mathematics, Minimal Vertex Cover
- Eric Weisstein's World of Mathematics, Pan Graph
- Index entries for linear recurrences with constant coefficients, signature (1,1).
Programs
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GAP
List([0..40],n->2*Fibonacci(n-1)); # Muniru A Asiru, Oct 07 2018
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Magma
[Lucas(n) - Fibonacci(n): n in [0..40]]; // Vincenzo Librandi, Sep 14 2014
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Maple
with(combinat): seq(2*fibonacci(n-1),n=0..40); # Muniru A Asiru, Oct 07 2018 a := n -> -2*I^n*ChebyshevU(n-2, -I/2): seq(simplify(a(n)), n = 0..39); # Peter Luschny, Dec 03 2023
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Mathematica
LinearRecurrence[{1, 1}, {2, 0}, 100] (* Vladimir Joseph Stephan Orlovsky, Jun 05 2011 *) Table[LucasL[n] - Fibonacci[n], {n, 0, 40}] (* Vincenzo Librandi, Sep 14 2014 *) Table[2 Fibonacci[n - 1], {n, 0, 20}] (* Eric W. Weisstein, Jun 30 2017 *) 2 Fibonacci[Range[0, 20] - 1] (* Eric W. Weisstein, Jun 30 2017 *) Subtract @@@ (Through[{LucasL, Fibonacci}[#]] & /@ Range[0, 20]) (* Eric W. Weisstein, Jun 30 2017 *) CoefficientList[Series[(2 (-1 + x))/(-1 + x + x^2), {x, 0, 20}], x] (* Eric W. Weisstein, Jun 30 2017 *)
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PARI
a(n)=fibonacci(n-1)<<1 \\ Charles R Greathouse IV, Jun 05 2011
Formula
From Philippe Deléham, Sep 20 2006: (Start)
a(0)=2, a(1)=0; for n > 1, a(n) = a(n-1) + a(n-2).
G.f. (2 - 2*x)/(1 - x - x^2).
a(0)=2 and a(n) = 2*A000045(n-1) for n > 0. (End)
a(n) = A006355(n) + 0^n. - M. F. Hasler, Nov 05 2014
a(n) = Lucas(n-2) + Fibonacci(n-2). - Bruno Berselli, May 27 2015
a(n) = 3*Fibonacci(n-2) + Fibonacci(n-5). - Bruno Berselli, Feb 20 2017
a(n) = 2*A212804(n). - Bruno Berselli, Feb 21 2017
E.g.f.: 2*exp(x/2)*(5*cosh(sqrt(5)*x/2) - sqrt(5)*sinh(sqrt(5)*x/2))/5. - Stefano Spezia, Apr 18 2022
Extensions
More terms from Philippe Deléham, Sep 20 2006
Corrected by T. D. Noe, Nov 01 2006
Comments