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A073089 (1/2)*(4n - 3 - Sum (k=1,n, A007400(k))). 3
0, 0, 1, 1, 1, 0, 0, 1, 1, 0, 1, 1, 0, 0, 0, 1, 1, 0, 1, 1, 1, 0, 0, 1, 0, 0, 1, 1, 0, 0, 0, 1, 1, 0, 1, 1, 1, 0, 0, 1, 1, 0, 1, 1, 0, 0, 0, 1, 0, 0, 1, 1, 1, 0, 0, 1, 0, 0, 1, 1, 0, 0, 0, 1, 1, 0, 1, 1, 1, 0, 0, 1, 1, 0, 1, 1, 0, 0, 0, 1, 1, 0, 1, 1, 1, 0, 0, 1, 0, 0, 1, 1, 0, 0, 0, 1, 0, 0, 1, 1, 1, 0, 0, 1, 1 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Table of n, a(n) for n=1..105.

FORMULA

Recurrence: a(1) = a(4n+2) = a(8n+7) = a(16n+13) = 0, a(4n) = a(8n+3) = a(16n+5) = 1, a(8n+1) = a(4n+1).

G.f.: The following series has a simple continued fraction expansion:

x + Sum_{n>=1} 1/x^(2^n-1) = [x; x, -x, -x, -x, x, ..., (-1)^a(n)*x, ...]. - Paul D. Hanna, Oct 19 2012

EXAMPLE

Let F(x) = x + 1/x + 1/x^3 + 1/x^7 + 1/x^15 + 1/x^31 +...+ 1/x^(2^n-1) +...

then F(x) = x + 1/(x + 1/(-x + 1/(-x + 1/(-x + 1/(x + 1/(x + 1/(-x + 1/(-x + 1/(x + 1/(-x + 1/(-x + 1/(x + 1/(x + 1/(x + 1/(-x + 1/(-x + 1/(x + 1/(-x + 1/(-x + 1/(-x + 1/(x +...+ 1/((-1)^a(n)*x +...)))))))))))))))))))))),

a continued fraction in which the partial quotients equal (-1)^a(n)*x. - Paul D. Hanna, Oct 19 2012

PROG

(PARI) a(n)=if(n<2, 0, if(n%8==1, a((n+1)/2), [1, -1, 0, 1, 1, 1, 0, 0, 1, -1, 0, 1, 1, 0, 0, 0][(n%16)+1])) /* from Ralf Stephan */

(PARI) /* Using the Continued Fraction, Print 2^N terms of this sequence: */

{N=10; CF=contfrac(x+sum(n=1, N, 1/x^(2^n-1)), 2^N); for(n=1, 2^N, print1((1-CF[n]/x)/2, ", "))} \\ Paul D. Hanna, Oct 19 2012

CROSSREFS

Cf. A007400.

Sequence in context: A165560 A014306 A138150 * A011657 A072126 A111113

Adjacent sequences:  A073086 A073087 A073088 * A073090 A073091 A073092

KEYWORD

easy,nonn,changed

AUTHOR

Benoit Cloitre, Aug 18 2002

STATUS

approved

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Last modified June 20 08:28 EDT 2013. Contains 226422 sequences.