A166446 Period 12: repeat [1,1,1,1,0,0,-1,-1,-1,-1,0,0].

1, 1, 1, 1, 0, 0, -1, -1, -1, -1, 0, 0, 1, 1, 1, 1, 0, 0, -1, -1, -1, -1, 0, 0, 1, 1, 1, 1, 0, 0, -1, -1, -1, -1, 0, 0, 1, 1, 1, 1, 0, 0, -1, -1, -1, -1, 0, 0, 1, 1, 1, 1, 0, 0, -1, -1, -1, -1, 0, 0, 1, 1, 1, 1, 0, 0, -1, -1, -1, -1, 0, 0, 1, 1, 1, 1, 0, 0

Offset: 0

Author

Paul Barry, Oct 13 2009

Keywords

• easy
• sign

Comments

a(n+2) is the Hankel transform of A110199. - Paul Barry, Jun 23 2010

Links

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

Crossrefs

Cf. A010892 (bisection).

Programs

Magma

&cat [[1,1,1,1,0,0,-1,-1,-1,-1,0,0]^^10]; // Vincenzo Librandi, May 15 2016

Mathematica

LinearRecurrence[{0,1,0,-1}, {1,1,1,1}, 50] (* G. C. Greubel, May 14 2016 *)

Formula

G.f.: (1+x)/(1-x^2+x^4).

a(n) = a(n-2)-a(n-4). - Wesley Ivan Hurt, May 09 2021

Extensions

Incorrect comment removed - R. J. Mathar, Oct 02 2012