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A083905 G.f.: 1/(1-x) * sum(k>=0, (-1)^k*x^2^(k+1)/(1+x^2^k)). 2
0, 1, 0, 0, -1, 1, 0, 1, 0, 2, 1, 0, -1, 1, 0, 0, -1, 1, 0, -1, -2, 0, -1, 1, 0, 2, 1, 0, -1, 1, 0, 1, 0, 2, 1, 0, -1, 1, 0, 2, 1, 3, 2, 1, 0, 2, 1, 0, -1, 1, 0, -1, -2, 0, -1, 1, 0, 2, 1, 0, -1, 1, 0, 0, -1, 1, 0, -1, -2, 0, -1, 1, 0, 2, 1, 0, -1, 1, 0, -1, -2, 0, -1, -2, -3, -1 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,10

COMMENTS

For all n, a(3*A006288(n)) = 0 as proved in Russian forum dxdy.ru - see link.

LINKS

Table of n, a(n) for n=1..86.

Discussion in Russian forum dxdy.ru

R. Stephan, Some divide-and-conquer sequences ...

R. Stephan, Table of generating functions

R. Stephan, Divide-and-conquer generating functions. I. Elementary sequences

FORMULA

a(1)=0, a(2n) = -a(n)+1, a(2n+1) = -a(n).

PROG

(PARI) for(n=1, 100, l=ceil(log(n)/log(2)); t=polcoeff(1/(1-x)*sum(k=0, l, (-1)^k*(x^2^(k+1))/(1+x^2^k)) + O(x^(n+1)), n); print1(t", "))

CROSSREFS

Cf. A065359, A023416.

a(n) = A030300(n) - A065359(n).

Sequence in context: A300060 A300056 A016102 * A179319 A257265 A045706

Adjacent sequences:  A083902 A083903 A083904 * A083906 A083907 A083908

KEYWORD

sign,easy

AUTHOR

Ralf Stephan, Jun 18 2003

STATUS

approved

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Last modified October 21 22:22 EDT 2018. Contains 316430 sequences. (Running on oeis4.)