This site is supported by donations to The OEIS Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A118831 Numerators of the convergents of the 2-adic continued fraction of zero given by A118830. 4
 -1, -1, 0, -1, 1, 1, 0, 1, -1, -1, 0, -1, 1, 1, 0, 1, -1, -1, 0, -1, 1, 1, 0, 1, -1, -1, 0, -1, 1, 1, 0, 1, -1, -1, 0, -1, 1, 1, 0, 1, -1, -1, 0, -1, 1, 1, 0, 1, -1, -1, 0, -1, 1, 1, 0, 1, -1, -1, 0, -1, 1, 1, 0, 1, -1, -1, 0, -1, 1, 1, 0, 1, -1, -1, 0, -1, 1, 1, 0, 1, -1, -1, 0, -1, 1, 1, 0, 1, -1, -1, 0, -1, 1, 1, 0, 1, -1, -1, 0, -1, 1, 1, 0, 1, -1, -1, 0 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 LINKS Index entries for linear recurrences with constant coefficients, signature (0, 0, 0, -1). FORMULA Period 8 sequence: [ -1,-1,0,-1,1,1,0,1]. G.f.: -x*(1+x+x^3)/(1+x^4). a(n)=1/8*{2*(n mod 8)-[(n+1) mod 8]+[(n+2) mod 8]-2*[(n+4) mod 8]+[(n+5) mod 8]-[(n+6) mod 8]} with n>=0 - Paolo P. Lava, Nov 27 2006 a(n)=-a(n-4). - R. J. Mathar, Jul 22 2009 EXAMPLE For n>=1, convergents A118831(k)/A118832(k) are: at k = 4*n: 1/(2*A080277(n)); at k = 4*n+1: 1/(2*A080277(n)-1); at k = 4*n+2: 1/(2*A080277(n)-2); at k = 4*n-1: 0. Convergents begin: -1/1, -1/2, 0/-1, -1/-2, 1/1, 1/0, 0/1, 1/8, -1/-7, -1/-6, 0/-1, -1/-10, 1/9, 1/8, 0/1, 1/24, -1/-23, -1/-22, 0/-1, -1/-26, 1/25, 1/24, 0/1, 1/32, -1/-31, -1/-30, 0/-1, -1/-34, 1/33, 1/32, 0/1, 1/64, ... PROG (PARI) {a(n)=local(p=-1, q=+2, v=vector(n, i, if(i%2==1, p, q*2^valuation(i/2, 2)))); contfracpnqn(v)[1, 1]} CROSSREFS Cf. A118830 (partial quotients), A118832 (denominators). Sequence in context: A188082 A046980 A152822 * A118828 A105234 A285599 Adjacent sequences:  A118828 A118829 A118830 * A118832 A118833 A118834 KEYWORD frac,sign AUTHOR Paul D. Hanna, May 01 2006 EXTENSIONS G.f. corrected by R. J. Mathar, Jul 22 2009 STATUS approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified May 24 11:23 EDT 2019. Contains 323529 sequences. (Running on oeis4.)