OFFSET
1,2
LINKS
Andrew Howroyd, Table of n, a(n) for n = 1..200
Index entries for linear recurrences with constant coefficients, signature (68,-708,2016).
FORMULA
a(n) = (23*56^(n-1) - 23*6^(n-1) - 25*(n-1)*6^(n-1))/500. - Andrew Howroyd, May 10 2020
From Colin Barker, Jul 16 2020: (Start)
G.f.: x^2*(2 + 3*x) / ((1 - 6*x)^2*(1 - 56*x)).
a(n) = 68*a(n-1) - 708*a(n-2) + 2016*a(n-3) for n>3.
(End)
MATHEMATICA
LinearRecurrence[{68, -708, 2016}, {0, 2, 139}, 20] (* Harvey P. Dale, Feb 03 2022 *)
PROG
(PARI) a(n) = {(23*56^(n-1) - 23*6^(n-1) - 25*(n-1)*6^(n-1))/500} \\ Andrew Howroyd, May 10 2020
(PARI) concat(0, Vec(x^2*(2 + 3*x) / ((1 - 6*x)^2*(1 - 56*x)) + O(x^20))) \\ Colin Barker, Jul 16 2020
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
R. H. Hardin, Dec 06 2008
EXTENSIONS
Terms a(8) and beyond from Andrew Howroyd, May 10 2020
STATUS
approved