A199928 Trisection 1 of A199802.

2, -1, -8, 15, 22, -104, 17, 510, -721, -1708, 5806, 1503, -31520, 31519, 121778, -312396, -233455, 1885694, -1152593, -8196936, 16079050, 21867343, -109306936, 24246207, 528076766, -780482080, -1726348607, 6132589566, 1190594623, -32799408980, 34705374038, 124349675919, -331866549712

Offset: 0

Author

N. J. A. Sloane, Nov 12 2011

Keywords

• sign
• easy

Comments

Also trisection 2 of A199803.

Links

• Colin Barker, Table of n, a(n) for n = 0..1000
• Hirschhorn, Michael D., Non-trivial intertwined second-order recurrence relations, Fibonacci Quart. 43 (2005), no. 4, 316-325. See p. 324.
• Index entries for linear recurrences with constant coefficients, signature (-1,-5,1,-1).

Programs

Mathematica

LinearRecurrence[{-1,-5,1,-1},{2,-1,-8,15},40] (* Harvey P. Dale, Aug 01 2021 *)

PARI

Vec((2 + x + x^2) / (1 + x + 5*x^2 - x^3 + x^4) + O(x^40)) \\ Colin Barker, Dec 27 2017

Formula

G.f.: ( 2+x+x^2 ) / ( 1+x+5*x^2-x^3+x^4 ). - R. J. Mathar, Jun 18 2014

a(n) = -a(n-1) - 5*a(n-2) + a(n-3) - a(n-4) for n>3. - Colin Barker, Dec 27 2017