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A081660 n+A001045(n+1). 2
1, 2, 5, 8, 15, 26, 49, 92, 179, 350, 693, 1376, 2743, 5474, 10937, 21860, 43707, 87398, 174781, 349544, 699071, 1398122, 2796225, 5592428, 11184835, 22369646, 44739269, 89478512, 178956999, 357913970, 715827913, 1431655796, 2863311563 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

LINKS

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

Index entries for linear recurrences with constant coefficients, signature (3,-1,-3,2)

FORMULA

a(n) = 2^(n+1)/3+n+(-1)^n/3.

G.f.: (1-x-2*x^3)/((1+x)*(1-2*x)*(1-x)^2). [Bruno Berselli, Aug 11 2013]

MATHEMATICA

Table[2^(n + 1)/3 + n + (-1)^n/3, {n, 0, 40}] (* Vincenzo Librandi, Aug 10 2013 *)

PROG

(MAGMA) [2^(n+1)/3+n+(-1)^n/3: n in [0..40]]; // Vincenzo Librandi, Aug 10 2013

CROSSREFS

Cf. A001045, A081659.

Sequence in context: A074027 A018156 A051293 * A285291 A065618 A257548

Adjacent sequences:  A081657 A081658 A081659 * A081661 A081662 A081663

KEYWORD

nonn,easy

AUTHOR

Paul Barry, Mar 26 2003

STATUS

approved

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Last modified July 9 16:50 EDT 2020. Contains 335545 sequences. (Running on oeis4.)