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A056469 Number of elements in the continued fraction for Sum_{k=0..n} 1/2^2^k. 5
2, 3, 4, 6, 10, 18, 34, 66, 130, 258, 514, 1026, 2050, 4098, 8194, 16386, 32770, 65538, 131074, 262146, 524290, 1048578, 2097154, 4194306, 8388610, 16777218, 33554434, 67108866, 134217730, 268435458, 536870914, 1073741826, 2147483650 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,1

LINKS

Vincenzo Librandi, Table of n, a(n) for n = 0..2000

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

FORMULA

a(0)=2; for n > 0, a(n) = 2^(n-1) + 2 = A052548(n-1) + 2.

a(n) = floor(2^(n-1) + 2). - Vincenzo Librandi, Sep 21 2011

From Colin Barker, Mar 22 2013: (Start)

a(n) = 3*a(n-1) - 2*a(n-2) for n > 2.

G.f.: -(x^2+3*x-2) / ((x-1)*(2*x-1)). (End)

MATHEMATICA

LinearRecurrence[{3, -2}, {2, 3, 4}, 40] (* Harvey P. Dale, Apr 23 2015 *)

PROG

(Sage) [floor(gaussian_binomial(n, 1, 2)+3) for n in xrange(-1, 32)] # Zerinvary Lajos, May 31 2009

(MAGMA) [Floor(2^(n-1)+2): n in [0..60]]; // Vincenzo Librandi, Sep 21 2011

CROSSREFS

Cf. A007400. Apart from initial term, same as A052548. See also A089985.

Sequence in context: A106511 A024490 A317200 * A228863 A004047 A093912

Adjacent sequences:  A056466 A056467 A056468 * A056470 A056471 A056472

KEYWORD

nonn,easy

AUTHOR

Benoit Cloitre, Dec 07 2002

STATUS

approved

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Last modified November 21 12:23 EST 2018. Contains 317449 sequences. (Running on oeis4.)