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A081003 a(n) = Fibonacci(4n+1) + 1, or Fibonacci(2n+1)*Lucas(2n). 1
2, 6, 35, 234, 1598, 10947, 75026, 514230, 3524579, 24157818, 165580142, 1134903171, 7778742050, 53316291174, 365435296163, 2504730781962, 17167680177566, 117669030460995, 806515533049394, 5527939700884758, 37889062373143907, 259695496911122586 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,1

REFERENCES

Hugh C. Williams, Edouard Lucas and Primality Testing, John Wiley and Sons, 1998, p. 75

LINKS

Nathaniel Johnston, Table of n, a(n) for n = 0..400

Index entries for linear recurrences with constant coefficients, signature (8,-8,1).

FORMULA

a(n) = 8*a(n-1) - 8*a(n-2) + a(n-3).

a(n) = 1+(1/2)*{[(7/2)-(3/2)*sqrt(5)]^n+[(7/2)+(3/2)*sqrt(5)]^n}+(1/10)*sqrt(5)*{[(7/2)+(3/2)*sqrt(5)]^n -[(7/2)-(3/2)*sqrt(5)]^n}, with n>=0. - Paolo P. Lava, Dec 01 2008

G.f.: (2-10*x+3*x^2)/((1-x)*(1-7*x+x^2)). - Colin Barker, Jun 24 2012

MAPLE

with(combinat): for n from 0 to 30 do printf(`%d, `, fibonacci(4*n+1)+1) od:  # James A. Sellers, Mar 03 2003

MATHEMATICA

Fibonacci[4*Range[0, 30]+1]+1 (* or *) LinearRecurrence[{8, -8, 1}, {2, 6, 35}, 30] (* Harvey P. Dale, Jul 20 2011 *)

PROG

(MAGMA) [Fibonacci(4*n+1) +1: n in [0..30]]; // Vincenzo Librandi, Apr 15 2011

(PARI) vector(30, n, n--; fibonacci(4*n+1)+1) \\ G. C. Greubel, Jul 15 2019

(Sage) [fibonacci(4*n+1)+1 for n in (0..30)] # G. C. Greubel, Jul 15 2019

(GAP) List([0..30], n-> Fibonacci(4*n+1)+1); # G. C. Greubel, Jul 15 2019

CROSSREFS

Cf. A000045 (Fibonacci numbers), A000032 (Lucas numbers).

Sequence in context: A135965 A018983 A279736 * A038181 A305275 A326090

Adjacent sequences:  A081000 A081001 A081002 * A081004 A081005 A081006

KEYWORD

nonn,easy

AUTHOR

R. K. Guy, Mar 01 2003

EXTENSIONS

More terms from James A. Sellers, Mar 03 2003

STATUS

approved

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Last modified December 12 15:11 EST 2019. Contains 329960 sequences. (Running on oeis4.)