OFFSET
0,2
LINKS
Colin Barker, Table of n, a(n) for n = 0..1000
Tomislav Doslic, I. Zubac, Counting maximal matchings in linear polymers, Ars Mathematica Contemporanea 11 (2016) 255-276. See Prop. 4.11.
Index entries for linear recurrences with constant coefficients, signature (2,2,-2).
FORMULA
a(n) = 2*a(n-1) + 2*a(n-2) - 2*a(n-3) for n>2. - Colin Barker, Apr 23 2017
PROG
(PARI) concat(0, Vec(2*x*(1 + 2*x) / (1 - 2*x - 2*x^2 + 2*x^3) + O(x^30))) \\ Colin Barker, Apr 23 2017
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
N. J. A. Sloane, Apr 23 2017
STATUS
approved