OFFSET
1,2
LINKS
Michael S. Branicky, Table of n, a(n) for n = 1..65
George Spahn, Counting Baxter Matrices, arXiv:2110.09688 [math.CO], 2021.
Index entries for linear recurrences with constant coefficients, signature (5,-10,10,-5,1).
FORMULA
From George Spahn, Oct 20 2021: (Start)
a(n) = 1/3*n^4 + 3*n^3 - 16/3*n^2 + 2*n + 3 for n >= 3.
G.f.: -x*(x^6 - 3*x^5 + 3*x^4 - 12*x^3 + 9*x^2 + 9*x + 1)/(x - 1)^5. (End)
MATHEMATICA
Rest@ CoefficientList[Series[-x (x^6 - 3 x^5 + 3 x^4 - 12 x^3 + 9 x^2 + 9 x + 1)/(x - 1)^5, {x, 0, 38}], x] (* Michael De Vlieger, Oct 20 2021 *)
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
N. J. A. Sloane, Sep 10 2021
EXTENSIONS
a(8)-a(38) from Michael S. Branicky, Sep 13 2021
STATUS
approved