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A068639 a(0) = 0, a(n) = a(n-1) + (-1)^p(n) for n >= 1, where p(n) = highest power of 2 dividing n. 2
0, 1, 0, 1, 2, 3, 2, 3, 2, 3, 2, 3, 4, 5, 4, 5, 6, 7, 6, 7, 8, 9, 8, 9, 8, 9, 8, 9, 10, 11, 10, 11, 10, 11, 10, 11, 12, 13, 12, 13, 12, 13, 12, 13, 14, 15, 14, 15, 16, 17, 16, 17, 18, 19, 18, 19, 18, 19, 18, 19, 20, 21, 20, 21, 22, 23, 22, 23, 24, 25, 24, 25, 24, 25, 24, 25, 26, 27, 26 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,5

REFERENCES

J.-P. Allouche and J. Shallit, The ring of k-regular sequences, II, Theoret. Computer Sci., 307 (2003), 3-29.

LINKS

Table of n, a(n) for n=0..78.

J.-P. Allouche, J. Shallit, The Ring of k-regular Sequences, II

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

R. Stephan, Table of generating functions

FORMULA

a(n)=(n+2*A065359(n))/3; a(n) is asymptotic to n/3. - Benoit Cloitre, Oct 04 2003

a(0)=0, a(2n) = -a(n) + n, a(2n+1) = -a(n) + n + 1. a(n) = (1/2) * (A050292(n) + A065639(n)). G.f. 1/2 * 1/(1-x) * sum(k>=0, (-1)^k*t/(1-t^2), t=x^2^k). - Ralf Stephan, Oct 17 2003

a(0)=0 then a(n)=ceiling(n/2)-a(n-ceiling(n/2)) - Benoit Cloitre, May 03 2004

PROG

(PARI) a(n)=if(n<1, 0, ceil(n/2)-a(n-ceil(n/2)))

CROSSREFS

Cf. A087733.

Sequence in context: A171465 A178620 A023524 * A074070 A304097 A251101

Adjacent sequences:  A068636 A068637 A068638 * A068640 A068641 A068642

KEYWORD

nonn,easy

AUTHOR

N. J. A. Sloane, Oct 01 2003

EXTENSIONS

More terms from John W. Layman and Robert G. Wilson v, Oct 02 2003

STATUS

approved

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Last modified October 19 09:28 EDT 2018. Contains 316339 sequences. (Running on oeis4.)