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A065034 a(n) = Lucas(2*n) + 1. 6
3, 4, 8, 19, 48, 124, 323, 844, 2208, 5779, 15128, 39604, 103683, 271444, 710648, 1860499, 4870848, 12752044, 33385283, 87403804, 228826128, 599074579, 1568397608, 4106118244, 10749957123, 28143753124, 73681302248, 192900153619, 505019158608, 1322157322204 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,1

LINKS

Harry J. Smith, Table of n, a(n) for n = 0..200

Index entries for linear recurrences with constant coefficients, signature (4,-4,1).

FORMULA

a(n) = F(2*n+1)+F(2*n-1)+1 = A005248(n) + 1.

a(n) = 4*a(n-1)-4*a(n-2)+a(n-3). G.f.: 1/(1-x) + (2-3*x)/(1-3*x+x^2). - R. J. Mathar, Jul 18 2009

a(n) = 1 + ((3-sqrt(5))/2)^n + ((3+sqrt(5))/2)^n. - Colin Barker, Nov 01 2016

MAPLE

a:= n-> (<<0|1>, <1|1>>^(2*n). <<2, 1>>)[1, 1]+1:

seq(a(n), n=0..30);  # Alois P. Heinz, Nov 01 2016

MATHEMATICA

LucasL[2 Range[30]]+1 (* Harvey P. Dale, Oct 21 2011 *)

PROG

(PARI) { for (n=0, 200, a=fibonacci(2*n + 1) + fibonacci(2*n - 1) + 1; write("b065034.txt", n, " ", a) ) } \\ Harry J. Smith, Oct 03 2009

(PARI) Vec((3-2*x)*(1-2*x)/((1-x)*(1-3*x+x^2)) + O(x^40)) \\ Colin Barker, Nov 01 2016

(MAGMA) [ Lucas(2*n) + 1: n in [0..210]]; // Vincenzo Librandi, Apr 15 2011

CROSSREFS

Cf. A000032, A000045, A005248, A005592.

Cf. A002878 (first differences). - R. J. Mathar, Jul 18 2009

Sequence in context: A061273 A254715 A107328 * A129285 A051440 A101932

Adjacent sequences:  A065031 A065032 A065033 * A065035 A065036 A065037

KEYWORD

nonn,easy

AUTHOR

N. J. A. Sloane, Nov 04 2001

EXTENSIONS

Prepended a(0)=3, Joerg Arndt, Nov 01 2016

STATUS

approved

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Last modified November 19 07:02 EST 2017. Contains 294915 sequences.