A131201 Period 24: repeat [0,1,2,5,2,9,0,9,8,5,8,1,0,-1,-2,-5,-2,-9,0,-9,-8,-5,-8,-1].

0, 1, 2, 5, 2, 9, 0, 9, 8, 5, 8, 1, 0, -1, -2, -5, -2, -9, 0, -9, -8, -5, -8, -1, 0, 1, 2, 5, 2, 9, 0, 9, 8, 5, 8, 1, 0, -1, -2, -5, -2, -9, 0, -9, -8, -5, -8, -1, 0, 1, 2, 5, 2, 9, 0, 9, 8, 5, 8, 1, 0, -1, -2, -5, -2, -9, 0, -9, -8, -5, -8, -1, 0, 1, 2, 5, 2, 9, 0, 9, 8, 5, 8, 1, 0, -1, -2, -5, -2, -9, 0, -9, -8, -5, -8, -1, 0, 1, 2, 5, 2, 9, 0, 9, 8

Offset: 0

Author

Paul Curtz, Sep 26 2007

Keywords

• sign
• easy

Links

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

Programs

PARI

a(n)=[0,1,2,5,2,9,0,9,8,5,8,1][n%12+1]*(-1)^(n\12) \\ Charles R Greathouse IV, Jul 26 2016

Formula

O.g.f.: x(x^2+1)(x^8+8x^7+4x^6+5x^4+4x^2+2x+1)/((x^4+1)(x^8-x^4+1)) . Also a(n)=b(n-2)+b(n), n>=2, where b(n) = 1, 2, 4, 0, 5, 0, 4, 8, 1, 0, 0, 0, -1, -2, -4, 0, -5, 0, -4, -8, -1, 0, 0, 0, extended with period 24. - R. J. Mathar, Jan 15 2008