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A206374 a(n) = (7*4^n - 1)/3. 4
2, 9, 37, 149, 597, 2389, 9557, 38229, 152917, 611669, 2446677, 9786709, 39146837, 156587349, 626349397, 2505397589, 10021590357, 40086361429, 160345445717, 641381782869, 2565527131477, 10262108525909, 41048434103637, 164193736414549, 656774945658197 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,1

COMMENTS

First bisection of A062092 and A081253, second bisection of A097163. - Bruno Berselli, Feb 12 2012

Except a(0)=2, this is the 3rd row of table A178415. - Michel Marcus, Apr 13 2015

LINKS

Vincenzo Librandi, Table of n, a(n) for n = 0..1000

Index entries for linear recurrences with constant coefficients, signature (5,-4).

FORMULA

G.f.: (2-x)/(1-5*x+4*x^2). - Bruno Berselli, Feb 12 2012

a(n) = A083597(n)+1. - Bruno Berselli, Feb 12 2012

a(n) = 4*a(n-1)+1 for n>0, a(0)=2. - Bruno Berselli, Oct 22 2015

a(n) = 7*A002450(n) + 2 . - Yosu Yurramendi, Jan 24 2017

MATHEMATICA

Table[(7(4^n) - 1)/3, {n, 0, 24}] (* Alonso del Arte, Feb 11 2012 *)

CoefficientList[Series[(2-x)/(1-5*x+4*x^2), {x, 0, 30}], x] (* or *) LinearRecurrence[{5, -4}, {2, 9}, 30] (* Vincenzo Librandi, Mar 20 2012 *)

PROG

(MAGMA) [(7*4^n-1)/3 : n in [0..30]];

(PARI) vector(20, n, (7*4^(n-1)-1)/3) \\ Derek Orr, Apr 12 2015

CROSSREFS

Cf. A002450, A072197; A002042 (first differences).

Sequence in context: A280351 A275425 A212386 * A037553 A178875 A012493

Adjacent sequences:  A206371 A206372 A206373 * A206375 A206376 A206377

KEYWORD

nonn,easy

AUTHOR

Brad Clardy, Feb 07 2012

STATUS

approved

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Last modified October 17 08:38 EDT 2018. Contains 316276 sequences. (Running on oeis4.)