A111914 Expansion of -x^2*(x^4-2*x^3+x^2-2*x+1)*(x+1)^2 / ((x-1)*(x^8-x^4+1)).

0, 0, 1, 1, -1, -3, -4, -4, -5, -7, -9, -9, -8, -8, -9, -9, -7, -5, -4, -4, -3, -1, 1, 1, 0, 0, 1, 1, -1, -3, -4, -4, -5, -7, -9, -9, -8, -8, -9, -9, -7, -5, -4, -4, -3, -1, 1, 1, 0, 0, 1, 1, -1, -3, -4, -4, -5, -7, -9, -9, -8, -8, -9, -9, -7, -5, -4, -4, -3, -1, 1, 1, 0, 0, 1, 1, -1, -3, -4, -4, -5, -7, -9, -9, -8, -8, -9, -9, -7, -5, -4, -4

Offset: 0

Author

Creighton Dement, Aug 20 2005

Keywords

• easy
• sign

Comments

It appears that (a(n)) has period 24.

Links

• Colin Barker, Table of n, a(n) for n = 0..1000
• Index entries for linear recurrences with constant coefficients, signature (1,0,0,1,-1,0,0,-1,1).

Crossrefs

Cf. A111912, A111913, A111915, A085846.

Programs

PARI

concat([0,0], Vec(x^2*(1 + x)^2*(1 - 2*x + x^2 - 2*x^3 + x^4) / ((1 - x)*(1 - x^4 + x^8)) + O(x^40))) \\ Colin Barker, May 18 2019

Formula

a(n) = a(n-1) + a(n-4) - a(n-5) - a(n-8) + a(n-9) for n > 8. - Colin Barker, May 18 2019