The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A089045 a(n) = a(n-1) + (-1)^floor(n/2)*a(floor(n/2)) with a(1) = 1. 1
 1, 0, -1, -1, -1, 0, 1, 0, -1, 0, 1, 1, 1, 0, -1, -1, -1, 0, 1, 1, 1, 0, -1, 0, 1, 0, -1, -1, -1, 0, 1, 0, -1, 0, 1, 1, 1, 0, -1, 0, 1, 0, -1, -1, -1, 0, 1, 1, 1, 0, -1, -1, -1, 0, 1, 0, -1, 0, 1, 1, 1, 0, -1, -1, -1, 0, 1, 1, 1, 0, -1, 0, 1, 0, -1, -1, -1, 0, 1, 1, 1, 0, -1, -1, -1, 0, 1, 0, -1, 0, 1, 1, 1, 0, -1, 0, 1, 0, -1, -1, -1, 0, 1, 0, -1, 0, 1, 1, 1, 0 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 LINKS Jinyuan Wang, Table of n, a(n) for n = 1..1000 FORMULA abs(a(n)) = A035263(n). PROG (PARI) lista(nn) = {my(v=vector(nn)); v[1]=1; for(n=2, nn, v[n] = v[n-1] + (-1)^floor(n/2)*v[floor(n/2)]); v; } \\ Jinyuan Wang, Feb 27 2020 CROSSREFS Cf. A001511, A035263. Sequence in context: A141260 A029883 A035263 * A259599 A070749 A285341 Adjacent sequences:  A089042 A089043 A089044 * A089046 A089047 A089048 KEYWORD sign AUTHOR Benoit Cloitre, Dec 02 2003 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 April 10 10:25 EDT 2021. Contains 342845 sequences. (Running on oeis4.)