A131036 First differences of A131711.

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

Offset: 0

Author

Paul Curtz, Sep 23 2007

Keywords

• sign

Comments

The equivalent operation on A001333 yields last digits A131707 and their first differences A131715.

Links

• Index entries for linear recurrences with constant coefficients, signature (-1,0,0,-1,-1,0,0,-1,-1).

Crossrefs

Cf. A131711.

Programs

Mathematica

Differences[PadRight[{},120,{0,1,2,5,2,9,0,9,8,5,8,1}]] (* Harvey P. Dale, Dec 29 2014 *)

Formula

a(n) = a(n-12).

From Chai Wah Wu, Jan 09 2021: (Start)

a(n) = - a(n-1) - a(n-4) - a(n-5) - a(n-8) - a(n-9) for n > 8.

G.f.: (x^8 + 8*x^7 + 4*x^6 + 5*x^4 + 4*x^2 + 2*x + 1)/(x^9 + x^8 + x^5 + x^4 + x + 1). (End)

Extensions

Edited by R. J. Mathar, Jul 07 2008