OFFSET
0,2
COMMENTS
Hankel transform of A079309.
LINKS
Index entries for linear recurrences with constant coefficients, signature (2,-3,2,-1).
FORMULA
a(n) = (2n+1)*cos(Pi*n/3) - (2n+5)*sin(Pi*n/3)/sqrt(3).
a(n) = 2*a(n-1) - 3*a(n-2) + 2*a(n-3) - a(n-4) for n > 3. - Jinyuan Wang, Apr 09 2020
MATHEMATICA
CoefficientList[Series[(1-4x-x^3)/(1-x+x^2)^2, {x, 0, 100}], x] (* or *) LinearRecurrence[{2, -3, 2, -1}, {1, -2, -7, -7}, 100] (* Harvey P. Dale, Sep 23 2021 *)
PROG
(PARI) Vec((1-4*x-x^3)/(1-x+x^2)^2 + O(x^62)) \\ Jinyuan Wang, Apr 09 2020
CROSSREFS
KEYWORD
sign,easy
AUTHOR
Paul Barry, Mar 15 2008
EXTENSIONS
More terms from Jinyuan Wang, Apr 09 2020
STATUS
approved