A141519 Period 10: repeat [-1, 1, -3, 7, -5, 3, -7, 9, -9, 5].

-1, 1, -3, 7, -5, 3, -7, 9, -9, 5, -1, 1, -3, 7, -5, 3, -7, 9, -9, 5, -1, 1, -3, 7, -5, 3, -7, 9, -9, 5, -1, 1, -3, 7, -5, 3, -7, 9, -9, 5, -1, 1, -3, 7, -5, 3, -7, 9, -9, 5, -1, 1, -3, 7, -5, 3, -7, 9, -9, 5, -1, 1, -3, 7, -5, 3, -7, 9, -9, 5, -1, 1, -3, 7, -5, 3, -7, 9, -9, 5, -1, 1, -3, 7, -5, 3, -7, 9, -9, 5, -1, 1, -3

Offset: 0

Author

Paul Curtz, Aug 11 2008

Keywords

• sign
• easy
• less

Comments

It appears that abs(a(n)) = abs(A001469(n+1)) mod 10.

It also appears that abs(a(n)) = abs(A228767(n+4)) mod 10. - Michel Marcus, Sep 04 2013

Links

• Index entries for linear recurrences with constant coefficients, signature (-1,-1,-1,-1,-1,-1,-1,-1,-1).

Crossrefs

Cf. A001469, A228767.

Programs

Mathematica

PadRight[{},120,{-1,1,-3,7,-5,3,-7,9,-9,5}] (* Harvey P. Dale, Mar 03 2023 *)

Formula

G.f.: ( -1-3*x^2+4*x^3+2*x^5-5*x^6-5*x^8-x^4+4*x^7 ) / ( (1+x)*(1+x+x^2+x^3+x^4)*(x^4-x^3+x^2-x+1) ). - R. J. Mathar, Oct 08 2011

a(n) = - Sum_{k=1..9} a(n-k). - Wesley Ivan Hurt, May 27 2021