The OEIS is supported by the many generous donors to the OEIS Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A143431 Periodic length 8 sequence [1, -1, 1, -1, -1, 1, -1, 1, ...]. 3
 1, -1, 1, -1, -1, 1, -1, 1, 1, -1, 1, -1, -1, 1, -1, 1, 1, -1, 1, -1, -1, 1, -1, 1, 1, -1, 1, -1, -1, 1, -1, 1, 1, -1, 1, -1, -1, 1, -1, 1, 1, -1, 1, -1, -1, 1, -1, 1, 1, -1, 1, -1, -1, 1, -1, 1, 1, -1, 1, -1, -1, 1, -1, 1, 1, -1, 1, -1, -1, 1, -1, 1, 1, -1, 1, -1, -1, 1, -1, 1, 1, -1, 1, -1, -1, 1, -1, 1, 1, -1, 1, -1, -1, 1, -1, 1, 1, -1, 1, -1, -1, 1 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,1 COMMENTS Nonsimple continued fraction expansion of (1+sqrt 5)/2= A001622. - R. J. Mathar, Mar 08 2012 LINKS Table of n, a(n) for n=0..101. FORMULA Euler transform of length 8 sequence [ -1, 1, 0, -2, 0, 0, 0, 1]. a(-1 - n) = a(n). a(n + 4) = - a(n). G.f.: (1 - x) * (1 + x^2) / (1 + x^4). a(n)=(1/4)*{-[(n+1) mod 8]+[(n+2) mod 8]-[(n+3) mod 8]+[(n+5) mod 8]-[(n+6) mod 8]+[(n+7) mod 8]}, with n>=0 [From Paolo P. Lava, Aug 25 2008] EXAMPLE 1 - x + x^2 - x^3 - x^4 + x^5 - x^6 + x^7 + x^8 - x^9 + x^10 - x^11 + ... PROG (PARI) a(n) = (-1)^(n + n\4) CROSSREFS Convolution inverse of A143432. Sequence in context: A112865 A114523 A130151 * A064179 A065357 A119665 Adjacent sequences: A143428 A143429 A143430 * A143432 A143433 A143434 KEYWORD sign,easy AUTHOR Michael Somos, Aug 14 2008 STATUS approved

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

Last modified September 22 21:28 EDT 2023. Contains 365531 sequences. (Running on oeis4.)